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A015286
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Gaussian binomial coefficient [ n,3 ] for q = -13.
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12
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1, -2040, 4508570, -9900819720, 21752862899691, -47790911017216080, 104996653267533662740, -230677643550873536294640, 506798783502833908602716981, -1113436927250681654567602842120
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OFFSET
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3,2
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REFERENCES
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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.
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LINKS
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FORMULA
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a(n) = Product_{i=1..3} ((-13)^(n-i+1) - 1)/((-13)^i - 1). - M. F. Hasler, Nov 03 2012
G.f.: x^3 / ( (x-1)*(2197*x+1)*(13*x+1)*(169*x-1) ). - R. J. Mathar, Aug 03 2016
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EXAMPLE
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MATHEMATICA
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PROG
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(Sage) [gaussian_binomial(n, 3, -13) for n in range(3, 13)] # Zerinvary Lajos, May 27 2009
(Magma) r:=3; q:=-13; [&*[(1-q^(n-i+1))/(1-q^i): i in [1..r]]: n in [r..20]]; // Vincenzo Librandi, Aug 02 2016
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CROSSREFS
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Cf. Gaussian binomial coefficients [n,r] for q=-13: A015265 (r=2), A015303 (r=4), A015321 (r=5), A015337 (r=6), A015355 (r=7), A015370 (r=8), A015385 (r=9), A015402 (r=10), A015422 (r=11), A015438 (r=12). - M. F. Hasler, Nov 03 2012
Fourth row (r=3) or column (resp. diagonal) in A015129 (read as square array resp. triangle). - M. F. Hasler, Nov 03 2012
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KEYWORD
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sign,easy
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AUTHOR
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STATUS
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approved
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