G.f.: Sum_{n>=0} x^n * Product_{k=1..n} (k + n*x) / (1 + k*x + n*x^2).
A204064
G.f.: Sum_{n>=0} x^n * Product_{k=1..n} (k + n*x) / (1 + k*x + n*x^2).
Terms
- a(0) =1a(1) =1a(2) =2a(3) =5a(4) =14a(5) =44a(6) =152a(7) =572a(8) =2324a(9) =10124a(10) =47012a(11) =231572a(12) =1204964a(13) =6599444a(14) =37924292a(15) =228033332a(16) =1431128804a(17) =9354072404a(18) =63548071172a(19) =447923400692
External references
- oeis: A204064