0,1

Table of n, a(n) for n=0..64.

a(n) <= n^2 + n + 2. For n>0, a(n) <= n^n + n + 1.

Least prime p such that triangular(3)*p is a triangular number is p=11, so a(3) = 11.

Cf. A000217, A068084, A225502.

Sequence in context: A224418 A220947 A224417 * A012960 A013117 A120864

Adjacent sequences: A225784 A225785 A225786 * A225788 A225789 A225790

nonn

Alex Ratushnyak, May 16 2013

approved