Double EEPROM memory entry Atmege 328p

how did you print this out?

+1 on ruining your EEPROM super fast... don't keep this code running.. put the code in the setup at least so that it only runs once

#include <EEPROM.h>
void setup() {
  for (int i = 0; i < 20; i++) EEPROM.write(i, 1);
}

void loop() {}