375903domain: NAppears in sequencesSum 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.at n=5A132303Partial sums of number of overpartitions (A015128).at n=29A277643