OFFSET
9,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 9..200
FORMULA
a(n) = Product_{i=1..9} (2^(n-i+1)-1)/(2^i-1), by definition. - Vincenzo Librandi, Aug 02 2016
G.f.: x^9/Product_{0<=i<=9} (1-2^i*x). - Robert Israel, Apr 23 2017
MAPLE
seq(eval(expand(QDifferenceEquations:-QBinomial(n, 9, q)), q=2), n=9..50);
MATHEMATICA
QBinomial[Range[9, 20], 9, 2] (* Harvey P. Dale, Jul 24 2016 *)
PROG
(Sage) [gaussian_binomial(n, 9, 2) for n in range(9, 21)] # Zerinvary Lajos, May 25 2009
(Magma) r:=9; q:=2; [&*[(1-q^(n-i+1))/(1-q^i): i in [1..r]]: n in [r..20]]; // Vincenzo Librandi, Aug 03 2016
(PARI) r=9; 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
KEYWORD
nonn
AUTHOR
EXTENSIONS
Offset changed by Vincenzo Librandi, Aug 03 2016
STATUS
approved