Increasing Number Triangle Using i + j - 1 in C#

Beginner
⏱️ 6 min read
📚 Updated: Aug 2025
🎯 2 Code Examples
Nested Loops
Increasing number triangle output (1, 2 3, 3 4 5, 4 5 6 7, 5 6 7 8 9) in C# programming

What You’ll Learn

How to compute each value using i + j - 1 to generate consecutive numbers on every row.

⭐ Pattern Output

For rows = 5, the pattern looks like this:

Output
1\n2 3\n3 4 5\n4 5 6 7\n5 6 7 8 9
1

Complete C# Program

This follows the reference program exactly: print (i + j - 1) for j = 1..i.

C#
using System;

namespace MyApp
{
    class Program
    {
        static void Main(string[] args)
        {
            int i, j;

            for (i = 1; i <= 5; i++)
            {
                for (j = 1; j <= i; j++)
                    Console.Write((i + j - 1) + " ");
                Console.WriteLine();
            }
        }
    }
}
2

Variation — User Input rows

Let the user choose the number of rows:

C#
using System;

namespace MyApp
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.Write("Enter rows: ");
            int rows = Convert.ToInt32(Console.ReadLine());
            if (rows < 1) return;

            for (int i = 1; i <= rows; i++)
            {
                for (int j = 1; j <= i; j++)
                    Console.Write((i + j - 1) + " ");
                Console.WriteLine();
            }
        }
    }
}

About the author

Mari Selvan M P
Mari Selvan M P 🔗

Developer, cloud engineer, and technical writer

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C# Number Pattern 32 C# Number Pattern 34