setup PWM for output ultrasound wave

According to my arithmetic:

OCR2A = 0, frequency = 2000000 Hz   <--- won't work in this case
OCR2A = 1, frequency = 1000000 Hz
OCR2A = 2, frequency = 666667 Hz
OCR2A = 3, frequency = 500000 Hz
OCR2A = 4, frequency = 400000 Hz
OCR2A = 5, frequency = 333333 Hz
OCR2A = 6, frequency = 285714 Hz
OCR2A = 7, frequency = 250000 Hz
OCR2A = 8, frequency = 222222 Hz
OCR2A = 9, frequency = 200000 Hz
OCR2A = 10, frequency = 181818 Hz
OCR2A = 11, frequency = 166667 Hz
OCR2A = 12, frequency = 153846 Hz
OCR2A = 13, frequency = 142857 Hz
OCR2A = 14, frequency = 133333 Hz
OCR2A = 15, frequency = 125000 Hz
OCR2A = 16, frequency = 117647 Hz
OCR2A = 17, frequency = 111111 Hz
OCR2A = 18, frequency = 105263 Hz
OCR2A = 19, frequency = 100000 Hz
OCR2A = 20, frequency = 95238 Hz
OCR2A = 21, frequency = 90909 Hz
OCR2A = 22, frequency = 86957 Hz
OCR2A = 23, frequency = 83333 Hz
OCR2A = 24, frequency = 80000 Hz
OCR2A = 25, frequency = 76923 Hz
OCR2A = 26, frequency = 74074 Hz
OCR2A = 27, frequency = 71429 Hz
OCR2A = 28, frequency = 68966 Hz
OCR2A = 29, frequency = 66667 Hz
OCR2A = 30, frequency = 64516 Hz
OCR2A = 31, frequency = 62500 Hz
OCR2A = 32, frequency = 60606 Hz
OCR2A = 33, frequency = 58824 Hz
OCR2A = 34, frequency = 57143 Hz
OCR2A = 35, frequency = 55556 Hz
OCR2A = 36, frequency = 54054 Hz
OCR2A = 37, frequency = 52632 Hz
OCR2A = 38, frequency = 51282 Hz
OCR2A = 39, frequency = 50000 Hz
OCR2A = 40, frequency = 48780 Hz
OCR2A = 41, frequency = 47619 Hz
OCR2A = 42, frequency = 46512 Hz
OCR2A = 43, frequency = 45455 Hz
OCR2A = 44, frequency = 44444 Hz
OCR2A = 45, frequency = 43478 Hz
OCR2A = 46, frequency = 42553 Hz
OCR2A = 47, frequency = 41667 Hz
OCR2A = 48, frequency = 40816 Hz
OCR2A = 49, frequency = 40000 Hz
OCR2A = 50, frequency = 39216 Hz
OCR2A = 51, frequency = 38462 Hz
OCR2A = 52, frequency = 37736 Hz
OCR2A = 53, frequency = 37037 Hz
OCR2A = 54, frequency = 36364 Hz
OCR2A = 55, frequency = 35714 Hz
OCR2A = 56, frequency = 35088 Hz
OCR2A = 57, frequency = 34483 Hz
OCR2A = 58, frequency = 33898 Hz
OCR2A = 59, frequency = 33333 Hz
OCR2A = 60, frequency = 32787 Hz
OCR2A = 61, frequency = 32258 Hz
OCR2A = 62, frequency = 31746 Hz
OCR2A = 63, frequency = 31250 Hz
OCR2A = 64, frequency = 30769 Hz
OCR2A = 65, frequency = 30303 Hz
OCR2A = 66, frequency = 29851 Hz
OCR2A = 67, frequency = 29412 Hz
OCR2A = 68, frequency = 28986 Hz
OCR2A = 69, frequency = 28571 Hz
OCR2A = 70, frequency = 28169 Hz
OCR2A = 71, frequency = 27778 Hz
OCR2A = 72, frequency = 27397 Hz
OCR2A = 73, frequency = 27027 Hz
OCR2A = 74, frequency = 26667 Hz
OCR2A = 75, frequency = 26316 Hz
OCR2A = 76, frequency = 25974 Hz
OCR2A = 77, frequency = 25641 Hz
OCR2A = 78, frequency = 25316 Hz
OCR2A = 79, frequency = 25000 Hz
OCR2A = 80, frequency = 24691 Hz
OCR2A = 81, frequency = 24390 Hz
OCR2A = 82, frequency = 24096 Hz
OCR2A = 83, frequency = 23810 Hz
OCR2A = 84, frequency = 23529 Hz
OCR2A = 85, frequency = 23256 Hz
OCR2A = 86, frequency = 22989 Hz
OCR2A = 87, frequency = 22727 Hz
OCR2A = 88, frequency = 22472 Hz
OCR2A = 89, frequency = 22222 Hz
OCR2A = 90, frequency = 21978 Hz
OCR2A = 91, frequency = 21739 Hz
OCR2A = 92, frequency = 21505 Hz
OCR2A = 93, frequency = 21277 Hz
OCR2A = 94, frequency = 21053 Hz
OCR2A = 95, frequency = 20833 Hz
OCR2A = 96, frequency = 20619 Hz
OCR2A = 97, frequency = 20408 Hz
OCR2A = 98, frequency = 20202 Hz
OCR2A = 99, frequency = 20000 Hz
OCR2A = 100, frequency = 19802 Hz
OCR2A = 101, frequency = 19608 Hz
OCR2A = 102, frequency = 19417 Hz
OCR2A = 103, frequency = 19231 Hz
OCR2A = 104, frequency = 19048 Hz
OCR2A = 105, frequency = 18868 Hz
OCR2A = 106, frequency = 18692 Hz
OCR2A = 107, frequency = 18519 Hz
OCR2A = 108, frequency = 18349 Hz
OCR2A = 109, frequency = 18182 Hz
OCR2A = 110, frequency = 18018 Hz
OCR2A = 111, frequency = 17857 Hz
OCR2A = 112, frequency = 17699 Hz
OCR2A = 113, frequency = 17544 Hz
OCR2A = 114, frequency = 17391 Hz
OCR2A = 115, frequency = 17241 Hz
OCR2A = 116, frequency = 17094 Hz
OCR2A = 117, frequency = 16949 Hz
OCR2A = 118, frequency = 16807 Hz
OCR2A = 119, frequency = 16667 Hz
OCR2A = 120, frequency = 16529 Hz
OCR2A = 121, frequency = 16393 Hz
OCR2A = 122, frequency = 16260 Hz
OCR2A = 123, frequency = 16129 Hz
OCR2A = 124, frequency = 16000 Hz
OCR2A = 125, frequency = 15873 Hz
OCR2A = 126, frequency = 15748 Hz
OCR2A = 127, frequency = 15625 Hz
OCR2A = 128, frequency = 15504 Hz
OCR2A = 129, frequency = 15385 Hz
OCR2A = 130, frequency = 15267 Hz
OCR2A = 131, frequency = 15152 Hz
OCR2A = 132, frequency = 15038 Hz
OCR2A = 133, frequency = 14925 Hz
OCR2A = 134, frequency = 14815 Hz
OCR2A = 135, frequency = 14706 Hz
OCR2A = 136, frequency = 14599 Hz
OCR2A = 137, frequency = 14493 Hz
OCR2A = 138, frequency = 14388 Hz
OCR2A = 139, frequency = 14286 Hz
OCR2A = 140, frequency = 14184 Hz
OCR2A = 141, frequency = 14085 Hz
OCR2A = 142, frequency = 13986 Hz
OCR2A = 143, frequency = 13889 Hz
OCR2A = 144, frequency = 13793 Hz
OCR2A = 145, frequency = 13699 Hz
OCR2A = 146, frequency = 13605 Hz
OCR2A = 147, frequency = 13514 Hz
OCR2A = 148, frequency = 13423 Hz
OCR2A = 149, frequency = 13333 Hz
OCR2A = 150, frequency = 13245 Hz
OCR2A = 151, frequency = 13158 Hz
OCR2A = 152, frequency = 13072 Hz
OCR2A = 153, frequency = 12987 Hz
OCR2A = 154, frequency = 12903 Hz
OCR2A = 155, frequency = 12821 Hz
OCR2A = 156, frequency = 12739 Hz
OCR2A = 157, frequency = 12658 Hz
OCR2A = 158, frequency = 12579 Hz
OCR2A = 159, frequency = 12500 Hz
OCR2A = 160, frequency = 12422 Hz
OCR2A = 161, frequency = 12346 Hz
OCR2A = 162, frequency = 12270 Hz
OCR2A = 163, frequency = 12195 Hz
OCR2A = 164, frequency = 12121 Hz
OCR2A = 165, frequency = 12048 Hz
OCR2A = 166, frequency = 11976 Hz
OCR2A = 167, frequency = 11905 Hz
OCR2A = 168, frequency = 11834 Hz
OCR2A = 169, frequency = 11765 Hz
OCR2A = 170, frequency = 11696 Hz
OCR2A = 171, frequency = 11628 Hz
OCR2A = 172, frequency = 11561 Hz
OCR2A = 173, frequency = 11494 Hz
OCR2A = 174, frequency = 11429 Hz
OCR2A = 175, frequency = 11364 Hz
OCR2A = 176, frequency = 11299 Hz
OCR2A = 177, frequency = 11236 Hz
OCR2A = 178, frequency = 11173 Hz
OCR2A = 179, frequency = 11111 Hz
OCR2A = 180, frequency = 11050 Hz
OCR2A = 181, frequency = 10989 Hz
OCR2A = 182, frequency = 10929 Hz
OCR2A = 183, frequency = 10870 Hz
OCR2A = 184, frequency = 10811 Hz
OCR2A = 185, frequency = 10753 Hz
OCR2A = 186, frequency = 10695 Hz
OCR2A = 187, frequency = 10638 Hz
OCR2A = 188, frequency = 10582 Hz
OCR2A = 189, frequency = 10526 Hz
OCR2A = 190, frequency = 10471 Hz
OCR2A = 191, frequency = 10417 Hz
OCR2A = 192, frequency = 10363 Hz
OCR2A = 193, frequency = 10309 Hz
OCR2A = 194, frequency = 10256 Hz
OCR2A = 195, frequency = 10204 Hz
OCR2A = 196, frequency = 10152 Hz
OCR2A = 197, frequency = 10101 Hz
OCR2A = 198, frequency = 10050 Hz
OCR2A = 199, frequency = 10000 Hz
OCR2A = 200, frequency = 9950 Hz
OCR2A = 201, frequency = 9901 Hz
OCR2A = 202, frequency = 9852 Hz
OCR2A = 203, frequency = 9804 Hz
OCR2A = 204, frequency = 9756 Hz
OCR2A = 205, frequency = 9709 Hz
OCR2A = 206, frequency = 9662 Hz
OCR2A = 207, frequency = 9615 Hz
OCR2A = 208, frequency = 9569 Hz
OCR2A = 209, frequency = 9524 Hz
OCR2A = 210, frequency = 9479 Hz
OCR2A = 211, frequency = 9434 Hz
OCR2A = 212, frequency = 9390 Hz
OCR2A = 213, frequency = 9346 Hz
OCR2A = 214, frequency = 9302 Hz
OCR2A = 215, frequency = 9259 Hz
OCR2A = 216, frequency = 9217 Hz
OCR2A = 217, frequency = 9174 Hz
OCR2A = 218, frequency = 9132 Hz
OCR2A = 219, frequency = 9091 Hz
OCR2A = 220, frequency = 9050 Hz
OCR2A = 221, frequency = 9009 Hz
OCR2A = 222, frequency = 8969 Hz
OCR2A = 223, frequency = 8929 Hz
OCR2A = 224, frequency = 8889 Hz
OCR2A = 225, frequency = 8850 Hz
OCR2A = 226, frequency = 8811 Hz
OCR2A = 227, frequency = 8772 Hz
OCR2A = 228, frequency = 8734 Hz
OCR2A = 229, frequency = 8696 Hz
OCR2A = 230, frequency = 8658 Hz
OCR2A = 231, frequency = 8621 Hz
OCR2A = 232, frequency = 8584 Hz
OCR2A = 233, frequency = 8547 Hz
OCR2A = 234, frequency = 8511 Hz
OCR2A = 235, frequency = 8475 Hz
OCR2A = 236, frequency = 8439 Hz
OCR2A = 237, frequency = 8403 Hz
OCR2A = 238, frequency = 8368 Hz
OCR2A = 239, frequency = 8333 Hz
OCR2A = 240, frequency = 8299 Hz
OCR2A = 241, frequency = 8264 Hz
OCR2A = 242, frequency = 8230 Hz
OCR2A = 243, frequency = 8197 Hz
OCR2A = 244, frequency = 8163 Hz
OCR2A = 245, frequency = 8130 Hz
OCR2A = 246, frequency = 8097 Hz
OCR2A = 247, frequency = 8065 Hz
OCR2A = 248, frequency = 8032 Hz
OCR2A = 249, frequency = 8000 Hz
OCR2A = 250, frequency = 7968 Hz
OCR2A = 251, frequency = 7937 Hz
OCR2A = 252, frequency = 7905 Hz
OCR2A = 253, frequency = 7874 Hz
OCR2A = 254, frequency = 7843 Hz
OCR2A = 255, frequency = 7813 Hz

OCR2B in each case should be (((OCR2A + 1) / 2) - 1)