lemma proved term proof

`triangular_2`

No prose has been written for this declaration yet. The Lean source and graph data below render without it.

formal statement (Lean)

  93@[simp] lemma triangular_2 : triangular 2 = 3 := rfl

Term-mode proof.

  94
  95/-- T(3) = 6. -/

Lean names referenced from this declaration's body.