Program to Display Fibonacci Sequence Using Recursion

function fib(n) {
  const fibArr = [0, 1]; // Initialize with the first two Fibonacci numbers
  if (n < 2) {
    return fibArr.slice(0, n + 1); // Return [0] for fib(0) and [0, 1] for fib(1)
  }

  function fibCal(num) {
    if (num < 2) {
      return; // Base case reached, no need to do anything
    }

    const nextFib = fibArr[fibArr.length - 1] + fibArr[fibArr.length - 2];
    fibArr.push(nextFib); // Calculate and append the next Fibonacci number
    fibCal(num - 1); // Recursively calculate the next number
  }

  fibCal(n - 1); // Start calculation from the 3rd Fibonacci number (index 2)
  return fibArr;
}

console.log(fib(100)); // Display Fibonacci sequence up to the 100th number

Time Complexity O(n)/Space Complexity O(n)