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 A015287 Gaussian binomial coefficient [ n,4 ] for q = -2. 3
 1, 11, 231, 3311, 56287, 875007, 14208447, 225683007, 3624203583, 57881286463, 926949282623, 14824402656063, 237244744338239, 3795481554332479, 60731179948567359, 971671079497526079, 15546959673214593855 (list; graph; refs; listen; history; text; internal format)
 OFFSET 4,2 REFERENCES J. Goldman and G.-C. Rota, The number of subspaces of a vector space, pp. 75-83 of W. T. Tutte, editor, Recent Progress in Combinatorics. Academic Press, NY, 1969. I. P. Goulden and D. M. Jackson, Combinatorial Enumeration. Wiley, NY, 1983, p. 99. M. Sved, Gaussians and binomials, Ars. Combinatoria, 17A (1984), 325-351. LINKS Vincenzo Librandi, Table of n, a(n) for n = 4..800 Index entries for linear recurrences with constant coefficients, signature (11,110,-440,-704,1024). FORMULA G.f.: x^4/((1-x)*(1+2*x)*(1-4*x)*(1+8*x)*(1-16*x)). - Bruno Berselli, Oct 30 2012 a(n) = (1 - 2^(2n-5)*(15-2^(2n-1)) - (-1)^n*5*2^(n-3)*(1-2^(2n-3)))/1215. - Bruno Berselli, Oct 30 2012 A015287(n) = T[n,4], where T is the triangular array A015109. - M. F. Hasler, Nov 04 2012 MATHEMATICA Table[QBinomial[n, 4, -2], {n, 4, 20}] (* Vincenzo Librandi, Oct 28 2012 *) PROG (Sage) [gaussian_binomial(n, 4, -2) for n in range(4, 21)] # Zerinvary Lajos, May 27 2009 (MAGMA) r:=4; q:=-2; [&*[(1-q^(n-i+1))/(1-q^i): i in [1..r]]: n in [r..20]]; // Vincenzo Librandi, Aug 02 2016 CROSSREFS Diagonal k=4 in the triangular array A015109. See there for further references and programs. - M. F. Hasler, Nov 04 2012 Sequence in context: A108518 A077736 A068122 * A254782 A169960 A045757 Adjacent sequences:  A015284 A015285 A015286 * A015288 A015289 A015290 KEYWORD nonn,easy AUTHOR Olivier Gérard, Dec 11 1999 STATUS approved

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Last modified February 20 17:04 EST 2020. Contains 332080 sequences. (Running on oeis4.)