G.f.: Sum_{n>=0} n! * x^n * Product_{k=1..n} (3 + k*x)/(1 + 3*k*x + k^2*x^2).
A221973
G.f.: Sum_{n>=0} n! * x^n * Product_{k=1..n} (3 + k*x)/(1 + 3*k*x + k^2*x^2).
Terms
- a(0) =1a(1) =3a(2) =10a(3) =39a(4) =183a(5) =1026a(6) =6695a(7) =49623a(8) =411050a(9) =3763599a(10) =37757055a(11) =411894882a(12) =4854301087a(13) =61459583007a(14) =831926801290
External references
- oeis: A221973