a(n) = Sum_{k=0..n} 2^(n-k) * binomial(3*n+1,k) * binomial(3*n-k-1,n-k).
A386863
a(n) = Sum_{k=0..n} 2^(n-k) * binomial(3*n+1,k) * binomial(3*n-k-1,n-k).
Terms
- a(0) =1a(1) =8a(2) =117a(3) =1948a(4) =34283a(5) =622272a(6) =11519692a(7) =216193460a(8) =4098365799a(9) =78293227384
External references
- oeis: A386863