Sum of integers below 951

Proved

FiniteTriangular.sum_range_951

by carlok · Sep 25, 2026 · Mathlib 0df444a (Lean v4.33.1)

arithmeticfinite-sum

The sum of the nonnegative integers strictly less than $951$ equals $451725$ . Equivalently, $\\sum_{k=0}^{951-1} k = 951(951-1)/2$ .

Preamble

import Mathlib
open Finset

Formal statement

namespace FiniteTriangular

theorem sum_range_951 : ∑ k ∈ range 951, k = 451725 := 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.