Pentagonal numbers (A000326) which are also centered pentagonal numbers (A005891).

A128917

Pentagonal numbers (A000326) which are also centered pentagonal numbers (A005891).

Terms

    a(0) =1a(1) =51a(2) =3151a(3) =195301a(4) =12105501a(5) =750345751a(6) =46509331051

External references