### Program to print prime number pyramid

I think you've already figured it out by looking at the above pattern that the numbers are all prime numbers. It takes number of lines $$(n)$$ as input and prints exactly $$n(n+1)/2$$ prime numbers. For example, if $$n=4$$ then we have $$4(4+1)/2 = 10$$ prime numbers in the pattern. Each line in the pattern has prime numbers exactly equal to the line number. For example, line 4 has 4 prime numbers, similarly, line 7 has 7 prime numbers.
$\therefore 1 + 2 + 3 + 4 +...+(n-1)+ n\\ = n(n+1)/2\\ or, \sum_{i=1}^{n} i = n(n+1)/2$
This follows the triangular number sequence.

My solution: