a(n) = n^3 * 2^n * binomial(3*n, n) / 3.
A378781
a(n) = n^3 * 2^n * binomial(3*n, n) / 3.
Terms
- a(0) =0a(1) =2a(2) =160a(3) =6048a(4) =168960a(5) =4004000a(6) =85542912a(7) =1701719040a(8) =32133218304a(9) =583116019200
External references
- oeis: A378781