a(n) = Sum_{k=0..n} binomial(n+k-1,n) * binomial(n+k,n)^2.
A374676
a(n) = Sum_{k=0..n} binomial(n+k-1,n) * binomial(n+k,n)^2.
Terms
- a(0) =1a(1) =4a(2) =117a(3) =4416a(4) =191025a(5) =8959098a(6) =443175257a(7) =22764880288
External references
- oeis: A374676