a(n) = Sum_{k=0..n} C(n,k) * C(4*n+k,k).
A156887
a(n) = Sum_{k=0..n} C(n,k) * C(4*n+k,k).
Terms
- a(0) =1a(1) =6a(2) =64a(3) =768a(4) =9708a(5) =126386a(6) =1676956a(7) =22548168a(8) =306167324a(9) =4188703512a(10) =57649462164a(11) =797294161824
External references
- oeis: A156887