Indices of centered pentagonal numbers (A005891) which are also octagonal numbers (A000567).

A253922

Indices of centered pentagonal numbers (A005891) which are also octagonal numbers (A000567).

Terms

    a(0) =1a(1) =56a(2) =297a(3) =26752a(4) =142913a(5) =12894168a(6) =68883529a(7) =6214961984a(8) =33201717825

External references