G.f. satisfies A^4 = BINOMIAL(A^3).

Terms

a(0) =1a(1) =1a(2) =4a(3) =28a(4) =286a(5) =3886a(6) =66260a(7) =1361972a(8) =32784353a(9) =904412593a(10) =28124223808a(11) =973106096392