a(n) = Sum_{k=1..n} binomial(n+k-1, n)^2 / n.
A129763
a(n) = Sum_{k=1..n} binomial(n+k-1, n)^2 / n.
Terms
- a(0) =1a(1) =5a(2) =39a(3) =369a(4) =3898a(5) =44239a(6) =528083a(7) =6544745a(8) =83496720a(9) =1090091650a(10) =14501708246a(11) =195954553755
External references
- oeis: A129763