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A022190 Gaussian binomial coefficients [n,7] for q = 2. 3
1, 255, 43435, 6347715, 866251507, 114429029715, 14877590196755, 1919209135381395, 246614610741341843, 31627961868755063955, 4052305562169692070035, 518946525150879134496915, 66441249531569955747981459 (list; graph; refs; listen; history; text; internal format)
OFFSET

7,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 7..200

FORMULA

G.f.: x^7/((1-x)*(1-2*x)*(1-4*x)*(1-8*x)*(1-16*x)*(1-32*x)*(1-64*x)*(1-128*x)). - Vincenzo Librandi, Aug 07 2016

a(n) = Product_{i=1..7} (2^(n-i+1)-1)/(2^i-1), by definition. - Vincenzo Librandi, Aug 02 2016

MATHEMATICA

Table[QBinomial[n, 7, 2], {n, 7, 24}] (* Vincenzo Librandi, Aug 02 2016 *)

PROG

(Sage) [gaussian_binomial(n, 7, 2) for n in xrange(7, 20)] # Zerinvary Lajos, May 25 2009

(MAGMA) r:=7; q:=2; [&*[(1-q^(n-i+1))/(1-q^i): i in [1..r]]: n in [r..20]]; // Vincenzo Librandi, Aug 02 2016

(PARI) r=7; q=2; for(n=r, 30, print1(prod(j=1, r, (1-q^(n-j+1))/(1-q^j)), ", ")) \\ G. C. Greubel, May 30 2018

CROSSREFS

Sequence in context: A221970 A177897 A160913 * A267545 A069383 A175824

Adjacent sequences:  A022187 A022188 A022189 * A022191 A022192 A022193

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Jun 14 1998

EXTENSIONS

Changed offset by Vincenzo Librandi, Aug 02 2016

STATUS

approved

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Last modified March 24 19:39 EDT 2019. Contains 321448 sequences. (Running on oeis4.)