a(n) = [x^n] Product_{k=1..n} (k + x + 2*k*x^2), for n >= 0.
A322892
a(n) = [x^n] Product_{k=1..n} (k + x + 2*k*x^2), for n >= 0.
Terms
- a(0) =1a(1) =1a(2) =9a(3) =45a(4) =717a(5) =6917a(6) =154877a(7) =2254625a(8) =64599201a(9) =1267075953a(10) =44097148953
External references
- oeis: A322892