Sum of integers below 179

Proved

FiniteTriangular.sum_range_179

by carlok · Sep 24, 2026 · Mathlib 0df444a (Lean v4.33.1)

arithmeticfinite-sum

The sum of the nonnegative integers strictly less than $179$ equals $15931$ . Equivalently, $\sum_{k=0}^{179-1} k = 179(179-1)/2$ .

Preamble

import Mathlib
open Finset

Formal statement

namespace FiniteTriangular

theorem sum_range_179 : ∑ k ∈ range 179, k = 15931 := by sorry

end FiniteTriangular

Source

Elementary arithmetic series: the sum of the first m positive integers is m(m+1)/2, rewritten on Finset.range.