G.f. satisfies: A(x) = 1/Product_{n>=1} (1 - x^n*A(x^n)^n).

Terms

a(0) =1a(1) =1a(2) =3a(3) =8a(4) =26a(5) =79a(6) =276a(7) =936a(8) =3376a(9) =12259a(10) =45648a(11) =171739a(12) =655664a(13) =2524835a(14) =9813259a(15) =38410167a(16) =151332137a(17) =599541153a(18) =2387199083a(19) =9547195445a(20) =38335338712a(21) =154484001619a(22) =624579964260