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 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. 4
 1, 3, 45, 831, 17181, 375903, 8530929, 198643455, 4714491357, 113550338127, 2767105469745, 68077260387315, 1688160321677025, 42142679453321307, 1058050429855640217, 26695057057648257231, 676431705046728704733 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS PROG (PARI) a(n)=sum(k=0, 2*n, polcoeff((1+x+x^2)^n, k)^3) CROSSREFS Cf. A132304, A132305. Sequence in context: A287031 A124487 A266698 * A298799 A202437 A008931 Adjacent sequences:  A132300 A132301 A132302 * A132304 A132305 A132306 KEYWORD nonn AUTHOR Paul D. Hanna, Aug 18 2007 STATUS approved

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Last modified August 3 11:57 EDT 2020. Contains 336198 sequences. (Running on oeis4.)