Indices of centered octagonal numbers (A016754) which are also centered heptagonal numbers (A069099).

A253447

Indices of centered octagonal numbers (A016754) which are also centered heptagonal numbers (A069099).

Terms

    a(0) =1a(1) =15a(2) =435a(3) =13021a(4) =390181a(5) =11692395a(6) =350381655a(7) =10499757241a(8) =314642335561

External references