G.f.: exp( Sum_{n>=1} [Sum_{k=0..n} C(n,k)^4 * x^k]^2 * x^n/n ).

A196560

G.f.: exp( Sum_{n>=1} [Sum_{k=0..n} C(n,k)^4 * x^k]^2 * x^n/n ).

Terms

    a(0) =1a(1) =1a(2) =3a(3) =20a(4) =205a(5) =2624a(6) =24793a(7) =283522a(8) =3639005a(9) =50426826a(10) =740744940a(11) =10801827249a(12) =163698355616

External references