References to A027907

Triangle of trinomial coefficients T(n,k) (n >= 0, 0<=k<=2n), read by rows (n-th row is obtained by expanding (1+x+x^2)^n).
1, 1, 1, 1, 1, 2, 3, 2, 1, 1, 3, 6, 7, 6, 3, 1, 1, 4, 10, 16, 19, 16, 10, 4, 1, 1, 5, 15, 30, 45

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