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%I #20 Sep 08 2022 08:44:46
%S 1,2801,6865251,16531644851,39709010932102,95347005938577702,
%T 228930106321885702602,549661852436388016181802,
%U 1319738336534843578720956303,3168691824510592423395247884703,7608029097572151019476340332672053
%N Gaussian binomial coefficients [ n,4 ] for q = 7.
%D F. J. MacWilliams and N. J. A. Sloane, The Theory of Error-Correcting Codes, Elsevier-North Holland, 1978, p. 698.
%H Vincenzo Librandi, <a href="/A022233/b022233.txt">Table of n, a(n) for n = 4..200</a>
%F a(n) = Product_{i=1..4} (7^(n-i+1)-1)/(7^i-1), by definition. - _Vincenzo Librandi_, Aug 06 2016
%F G.f.: x^4/((1 - x)*(1 - 7*x)*(1 - 49*x)*(1 - 343*x)*(1 - 2401*x)). - _Ilya Gutkovskiy_, Aug 06 2016
%t Table[QBinomial[n, 4, 7], {n, 4, 20}] (* _Vincenzo Librandi_, Aug 06 2016 *)
%o (Sage) [gaussian_binomial(n,4,7) for n in range(4,15)] # _Zerinvary Lajos_, May 27 2009
%o (Magma) r:=4; q:=7; [&*[(1-q^(n-i+1))/(1-q^i): i in [1..r]]: n in [r..20]]; // _Vincenzo Librandi_, Aug 06 2016
%o (PARI) r=4; q=7; for(n=r,30, print1(prod(j=1,r,(1-q^(n-j+1))/(1-q^j)), ", ")) \\ _G. C. Greubel_, Jun 13 2018
%K nonn
%O 4,2
%A _N. J. A. Sloane_
%E Offset changed by _Vincenzo Librandi_, Aug 06 2016