A022233 Gaussian binomial coefficients [ n,4 ] for q = 7.

1, 2801, 6865251, 16531644851, 39709010932102, 95347005938577702, 228930106321885702602, 549661852436388016181802, 1319738336534843578720956303, 3168691824510592423395247884703, 7608029097572151019476340332672053

Offset

4,2

References

F. J. MacWilliams and N. J. A. Sloane, The Theory of Error-Correcting Codes, Elsevier-North Holland, 1978, p. 698.

Links

Vincenzo Librandi, Table of n, a(n) for n = 4..200

Formula

a(n) = Product_{i=1..4} (7^(n-i+1)-1)/(7^i-1), by definition. - Vincenzo Librandi, Aug 06 2016

G.f.: x^4/((1 - x)*(1 - 7*x)*(1 - 49*x)*(1 - 343*x)*(1 - 2401*x)). - Ilya Gutkovskiy, Aug 06 2016

Mathematica

Table[QBinomial[n, 4, 7], {n, 4, 20}] (* Vincenzo Librandi, Aug 06 2016 *)

Prog

(Sage) [gaussian_binomial(n, 4, 7) for n in range(4, 15)] # Zerinvary Lajos, May 27 2009
(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
(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

Crossrefs

Sequence in context: A115471 A292011 A306849 * A102170 A031551 A031731

Adjacent sequences: A022230 A022231 A022232 * A022234 A022235 A022236

Keyword

nonn

Author

N. J. A. Sloane

Extensions

Offset changed by Vincenzo Librandi, Aug 06 2016

Status

approved