T(n+1)=T(n)+n+1
From specialfunctionswiki
Theorem
The following formula holds for $n=1,2,3,\ldots$: $$T(n+1) = T(n)+n+1,$$ where $T(n)$ denotes the $n$th triangular number.
Proof
References
- V.E. Hoggatt, Jr and Marjorie Bicknell: Triangular numbers (1974)... (previous)... (next) $(1.2)$
