a(n) = (3*n+1) * (4*n+1)^(n-2) * 5^n.

A251695

a(n) = (3*n+1) * (4*n+1)^(n-2) * 5^n.

Terms

    a(0) =1a(1) =4a(2) =175a(3) =16250a(4) =2348125a(5) =463050000a(6) =115966796875

External references