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Gaussian binomial coefficient [ n,3 ] for q = 4.
(Formerly M5360)
2

%I M5360 #43 Jul 14 2023 14:39:05

%S 1,85,5797,376805,24208613,1550842085,99277752549,6354157930725,

%T 406672215935205,26027119554103525,1665737215212030181,

%U 106607206793565997285,6822861635108183247077,436663151052043168024805,27946441769812674154891493

%N Gaussian binomial coefficient [ n,3 ] for q = 4.

%D 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.

%D I. P. Goulden and D. M. Jackson, Combinatorial Enumeration. Wiley, NY, 1983, p. 99.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%D M. Sved, Gaussians and binomials, Ars. Combinatoria, 17A (1984), 325-351.

%H Vincenzo Librandi, <a href="/A006106/b006106.txt">Table of n, a(n) for n = 3..200</a>

%H Simon Plouffe, <a href="https://arxiv.org/abs/0911.4975">Approximations de séries génératrices et quelques conjectures</a>, Dissertation, Université du Québec à Montréal, 1992; arXiv:0911.4975 [math.NT], 2009.

%H Simon Plouffe, <a href="/A000051/a000051_2.pdf">1031 Generating Functions</a>, Appendix to Thesis, Montreal, 1992

%H M. Sved, <a href="/A006095/a006095.pdf">Gaussians and binomials</a>, Ars. Combinatoria, 17A (1984), 325-351. (Annotated scanned copy)

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (85, -1428, 5440, -4096).

%F G.f.: x^3/((1-x)*(1-4*x)*(1-16*x)*(1-64*x)). - _Simon Plouffe_ in his 1992 dissertation

%F a(n) = Product_{i=1..3} (4^(n-i+1)-1)/(4^i-1), by definition. - _Vincenzo Librandi_, Aug 07 2016

%t Table[QBinomial[n, 3, 4], {n, 3, 20}] (* _Vincenzo Librandi_, Aug 07 2016 *)

%o (Sage) [gaussian_binomial(n,3,4) for n in range(3,15)] # _Zerinvary Lajos_, May 27 2009

%o (Magma) r:=3; q:=4; [&*[(1-q^(n-i+1))/(1-q^i): i in [1..r]]: n in [r..20]]; // _Vincenzo Librandi_, Aug 07 2016

%K nonn,easy

%O 3,2

%A _N. J. A. Sloane_