a(n) = Sum_{k>=1} (4*k - 1)^n / 2^k.

A355220

a(n) = Sum_{k>=1} (4*k - 1)^n / 2^k.

Terms

    a(0) =1a(1) =7a(2) =81a(3) =1399a(4) =32289a(5) =931687a(6) =32259441a(7) =1303134679a(8) =60160827969

External references