a(n) = Sum_{k=0..n} binomial(4*n,k) * binomial(2*n-k,n-k).
A386919
a(n) = Sum_{k=0..n} binomial(4*n,k) * binomial(2*n-k,n-k).
Terms
- a(0) =1a(1) =6a(2) =58a(3) =624a(4) =7050a(5) =81926a(6) =969640a(7) =11624976a(8) =140708682a(9) =1715727090a(10) =21043480458a(11) =259331888712
External references
- oeis: A386919