Sum of cubes of trinomial coefficients: a(n) = Sum_{k=0..2n} trinomial(n,k)^3 where trinomial(n,k) = [x^k] (1 + x + x^2)^n.
A132303
Sum of cubes of trinomial coefficients: a(n) = Sum_{k=0..2n} trinomial(n,k)^3 where trinomial(n,k) = [x^k] (1 + x + x^2)^n.
Terms
- a(0) =1a(1) =3a(2) =45a(3) =831a(4) =17181a(5) =375903a(6) =8530929a(7) =198643455a(8) =4714491357a(9) =113550338127
External references
- oeis: A132303