a(n) = Sum_{k=0..n} binomial(n, k) * binomial((n-k)*k, k).
A264409
a(n) = Sum_{k=0..n} binomial(n, k) * binomial((n-k)*k, k).
Terms
- a(0) =1a(1) =1a(2) =3a(3) =10a(4) =53a(5) =376a(6) =3187a(7) =31312a(8) =348833a(9) =4318804a(10) =58583231a(11) =862021084a(12) =13650998473a(13) =231123405124
External references
- oeis: A264409