E.g.f. satisfies A(x) = exp(x*A(x^7/7!)).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =1a(7) =1a(8) =9a(9) =73a(10) =361a(11) =1321a(12) =3961a(13) =10297a(14) =24025a(15) =77221a(16) =926641a(17) =10696401a(18) =84365425a(19) =499445857a(20) =2395445521a(21) =9778915441a(22) =36584246161a(23) =248210675593