LED pin 13 not flashing properly This is my first program on Arduino Uno (the starter kit), although I do have prior experience with programming (JavaScript, coding class last year 7th grade). It blinks the internal led (pin 13) in a Morse Code message:

.... . .-.. .-.. ---   .-- --- .-. .-.. -..
. = dit(); 

- = dah(); 

(interval between parts of letter) = wip(); 

(interval between letters/words) = wah();


Here's my code:
/*
 * Roman's first program
 * Decipher the message!
*/

int ledPin = 13;
int index = 0;

void setup() {
  //initialize pins as outputs
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  int sequence[] = {1,0,1,0,1,0,1,3,1,3,1,0,2,0,1,0,1,3,1,0,2,0,1,0,1,3,2,0,2,0,2,3,3,3,1,0,2,0,2,3,2,0,2,0,2,3,1,0,2,0,1,3,1,0,2,0,1,0,1,3,2,0,1,0,1};
  int arrLength = sizeof(sequence)/sizeof(int); //however THIS works?!
  if (index &lt; arrLength-1) { //0-based array
    index++;
  } else {
     index = 0; //restart the sequence once finished
  }
  if (sequence[index] == 0) {
    wip();
  } else if (sequence[index] == 1) {
    dit();
  } else if (sequence[index] == 2) { 
    dah();
  } else if (sequence[index] == 3) { //because sometimes I the values are screwed past arrLength...
    wah();
  }
  //Serial.println(String(sequence[index])+&quot; , &quot;+String(index));
}

void dit () {
  digitalWrite(pinMode, HIGH); 
  delay(300); 
  digitalWrite(pinMode, LOW);
}

void dah () {
  digitalWrite(pinMode, HIGH); 
  delay(900); 
  digitalWrite(pinMode, LOW);
}

void wip () {
  delay(900);
}

void wah () {
  delay(2100);
}

Yet nothing is happening, except for the four/five startup flashes on the led when I restart it (red button). And yes, I saved and compiled.
Well, mainly digitalWrite(pinMode, HIGH); looks suspicious. I though you called LED pin as ledPin

If you fix this, it should be working. As this one is working too, it's just simplified a little:

int ledPin = 13;
int index = 0;
const int8_t sequence[] = {1,0,1,0,1,0,1,3,1,3,1,0,2,0,1,0,1,3,1,0,2,0,1,0,1,3,2,0,2,0,2,3,3,3,1,0,2,0,2,3,2,0,2,0,2,3,1,0,2,0,1,3,1,0,2,0,1,0,1,3,2,0,1,0,1};
int arrLength     = sizeof(sequence);


void setup() {
  pinMode(ledPin, OUTPUT);
  Serial.begin(57600);
}

void loop() {
  Serial.println(String(sequence[index])+" , "+String(index));
  switch (sequence[index++]) {
    case 0: wip(); break;
    case 1: dit(); break;
    case 2: dah(); break;
    case 3: wah(); break;
  }
  if (index == arrLength) {
    index = 0;
  }
}

void dit () {
  digitalWrite(ledPin, HIGH); 
  delay(300); 
  digitalWrite(ledPin, LOW);
}

void dah () {
  digitalWrite(ledPin, HIGH); 
  delay(900); 
  digitalWrite(ledPin, LOW);
}

void wip () {
  delay(900);
}

void wah () {
  delay(2100);
}