a(n) = Sum_{k=0..n} 2^(n-k) * binomial(n+4,k+4) * binomial(2*k+8,k+8).
A387274
a(n) = Sum_{k=0..n} 2^(n-k) * binomial(n+4,k+4) * binomial(2*k+8,k+8).
Terms
- a(0) =1a(1) =20a(2) =246a(3) =2408a(4) =20636a(5) =162288a(6) =1203000a(7) =8546208a(8) =58823919a(9) =395245708a(10) =2606333730a(11) =16933021560a(12) =108703640136a(13) =691068080928
External references
- oeis: A387274