G.f.: Sum_{n>=0} 1/(1+x)^(n^2-n) * Product_{k=1..n} ((1+x)^(2*k-1) - 1).
A207557
G.f.: Sum_{n>=0} 1/(1+x)^(n^2-n) * Product_{k=1..n} ((1+x)^(2*k-1) - 1).
Terms
- a(0) =1a(1) =1a(2) =3a(3) =12a(4) =64a(5) =420a(6) =3276a(7) =29581a(8) =303389a(9) =3483053a(10) =44245695a(11) =616103046a(12) =9330961666a(13) =152700926414
External references
- oeis: A207557