Coefficient of z^(3*n) in the expansion of (1 + 9*z + 9*z^2 + z^3)^(2*n).
A300057
Coefficient of z^(3*n) in the expansion of (1 + 9*z + 9*z^2 + z^3)^(2*n).
Terms
- a(0) =1a(1) =164a(2) =47148a(3) =15454820a(4) =5361965980
External references
- oeis: A300057