G.f.: A(x) = exp( Sum_{n>=1} A005261(n)/2*x^n/n ) where A005261(n) = Sum_{k=0..n} C(n,k)^5.

A218118

G.f.: A(x) = exp( Sum_{n>=1} A005261(n)/2*x^n/n ) where A005261(n) = Sum_{k=0..n} C(n,k)^5.

Terms

    a(0) =1a(1) =1a(2) =9a(3) =90a(4) =1350a(5) =22623a(6) =430338a(7) =8786367a(8) =190473510a(9) =4314088755a(10) =101271596421

External references