int ledpin[]  = {0,1,2,3,4,5,6,7,8,9,10,11,12};

void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
 randomSeed(analogRead(A0));
   for(int i = 3;i <= 12;i++){
   pinMode(ledpin[i], OUTPUT);
 }
}

void loop() {
  // put your main code here, to run repeatedly:
 
   for(int d = 0;d <= 12;d++){
     for(int b = 12;b <= 12;b++){
int rand = random(ledpin[d], ledpin[b]);
digitalWrite(rand, HIGH);
delay(1000);
digitalWrite(rand, LOW);
delay(1000);
     }
   }
}