a(n) = Sum_{k=0..n} binomial(4*n+2*k,n-k).
A390408
a(n) = Sum_{k=0..n} binomial(4*n+2*k,n-k).
Terms
- a(0) =1a(1) =5a(2) =39a(3) =328a(4) =2849a(5) =25197a(6) =225442a(7) =2033451a(8) =18451513a(9) =168203885a(10) =1538997045a(11) =14123566830a(12) =129938620258
External references
- oeis: A390408