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 A192441 Coefficient of x^(2*n) in the expansion of (1 + x^3 + x^4)^n. 2
 1, 0, 2, 3, 6, 30, 35, 210, 350, 1344, 3402, 9240, 29139, 72072, 231660, 603603, 1814670, 5095376, 14507324, 42401502, 118974466, 349305120, 990073812, 2877816304, 8272748675, 23852438880, 69116072950, 198980348385, 577566713520, 1667118322590, 4834810467135 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..200 FORMULA a(n) = Sum_{k=ceiling(n/2)..floor(2*n/3)} binomial(n,k)*binomial(k,2*n-3*k). - R. J. Mathar, Jul 01 2011 PROG (PARI) a(n)=polcoeff((1+x^3+x^4)^n, 2*n); (Maxima) makelist((coeff(expand((1+x^3+x^4)^n), x, 2*n)), n, 0, 30); /* Bruno Berselli, Jul 01 2011 */ (Magma) P:=PolynomialRing(Integers()); [ Coefficients((1+x^3+x^4)^n)[ 2*n+1 ]: n in [0..30] ]; // Bruno Berselli, Jul 01 2011 CROSSREFS Cf. A002426, A192440. Sequence in context: A277809 A051717 A330030 * A108326 A002234 A074005 Adjacent sequences: A192438 A192439 A192440 * A192442 A192443 A192444 KEYWORD nonn AUTHOR Joerg Arndt, Jul 01 2011 STATUS approved

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Last modified March 30 19:10 EDT 2023. Contains 361622 sequences. (Running on oeis4.)