Grandson's First Go with Arduino

My grandson (10 years old) and I decided we both wanted to learn Raspberry Pi and Arduino the latter in this case.
We have the breadboard set with 7 leds, all is fine they turn on as expected, they are on pins 1-7 on the Arduino. When it does the loop through to turn them off they all get turned off except for led 1. Here is the code we are using.
Any suggestions would be apprecited.
Thanks
MW/LW

// Declarations
 
 int delayTime = 1000;          // Declare a delay period of 1 second
 int LEDs[] = {1,2,3,4,5,6,7};  // The Array
 int pincount = 7;              // Number of PINs starting at position 1 on the board

  
void setup()
{
  for(int count=0; count<pincount; count++){
  pinMode(LEDs[count], OUTPUT); // "LEDs" initialised as O/P for LOOP
 }
   
}

void loop()
{
  
  for(int count=0; count<=pincount; count++){
   digitalWrite(LEDs[count], HIGH); // Turn all LEDs in the array ON
   delay(delayTime);
  }
  
  for(int count=0; count<=pincount; count++){
    digitalWrite(LEDs[count], LOW); // Turn LEDs in the array OFF DOES NOT TURN OFF LED 1 which is in slot 1 on the board
  }
  
}

they are on pins 1-7

Don't us pin 1. It is used by the hardwareSerial interface