a(n) = (1/(n+1)) * Sum_{k=0..n} binomial(n+k,k) * binomial(n*(n+1),n-k).
A366012
a(n) = (1/(n+1)) * Sum_{k=0..n} binomial(n+k,k) * binomial(n*(n+1),n-k).
Terms
- a(0) =1a(1) =2a(2) =13a(3) =156a(4) =2833a(5) =70098a(6) =2214280a(7) =85464984a(8) =3906724321a(9) =206648387550
External references
- oeis: A366012