O.g.f.: A(x) = Sum_{n>=0} x^n / Product_{k=0..n} (1 - k*(k+1)*x).
A135921
O.g.f.: A(x) = Sum_{n>=0} x^n / Product_{k=0..n} (1 - k*(k+1)*x).
Terms
- a(0) =1a(1) =1a(2) =3a(3) =13a(4) =81a(5) =669a(6) =6955a(7) =88505a(8) =1346209a(9) =23998521a(10) =493956467a(11) =11596542533a(12) =307301505073
External references
- oeis: A135921