Positive triangular numbers (A000217) that are pentagonal numbers (A000326) divided by 2.
A259156
Positive triangular numbers (A000217) that are pentagonal numbers (A000326) divided by 2.
Terms
- a(0) =6a(1) =105a(2) =58311a(3) =1008910a(4) =559902916a(5) =9687554415
External references
- oeis: A259156