Задача: Tribonacci Triangle

Решение

using System;

namespace TribonacciTriangle {
  class Program {
    static void Main() {
      long firstNumber = long.Parse(Console.ReadLine());
      long secondNumber = long.Parse(Console.ReadLine());
      long thirdNumber = long.Parse(Console.ReadLine());
      int linesCount = int.Parse(Console.ReadLine());

      Console.WriteLine(firstNumber);
      Console.WriteLine(secondNumber + " " + thirdNumber);

      int membersCount = 0;
      for (int i = 1; i <= linesCount; i++) {
        membersCount += i;
      }
      int nextLine = 3;
      int lineSize = 0;
      for (int i = 4; i <= membersCount; i++) {
        long currentNumber = firstNumber + secondNumber + thirdNumber;
        firstNumber = secondNumber;
        secondNumber = thirdNumber;
        thirdNumber = currentNumber;
        Console.Write(currentNumber + " ");
        lineSize++;
        if (lineSize == nextLine) {
          Console.WriteLine();
          nextLine += 1;
          lineSize = 0;
        }
      }
    }
  }
}