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

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =5a(5) =15a(6) =46a(7) =149a(8) =495a(9) =1682a(10) =5806a(11) =20322a(12) =71919a(13) =256936a(14) =925298a(15) =3355509a(16) =12242471a(17) =44906105a(18) =165503745a(19) =612575796a(20) =2276024836a(21) =8485972958a(22) =31739314999a(23) =119054638380a(24) =447759005393