G.f.: exp( Sum_{n>=1} [Sum_{k=0..n} C(n,k)^4 * x^k] * x^n/n ), an integer series in x.

A166898

G.f.: exp( Sum_{n>=1} [Sum_{k=0..n} C(n,k)^4 * x^k] * x^n/n ), an integer series in x.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =10a(4) =38a(5) =137a(6) =646a(7) =3241a(8) =15623a(9) =79439a(10) =427562a(11) =2317396a(12) =12715372a(13) =71543343a(14) =408543758a(15) =2353591560a(16) =13717994046a(17) =80827739181a(18) =480016288156

External references