internal class Program { private static void Main(string[] args) { long limit = 100; Console.WriteLine($"Count of divisors for the first {limit} positive integers:"); long count = 0; for (long n = 1; count < limit; ++n) { Console.Write($"{DivisorCount(n),3} "); ++count; if (count % 20 == 0) { Console.WriteLine(); } } } private static long DivisorCount(long n) { long total = 1; // Deal with powers of 2 first for (; (n & 1) == 0; n >>= 1) { ++total; } // Odd prime factors up to the square root for (long p = 3; p * p <= n; p += 2) { long count = 1; for (; n % p == 0; n /= p) { ++count; } total *= count; } // If n > 1 then it's prime if (n > 1) { total *= 2; } return total; } }