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A022253 Gaussian binomial coefficients [ n,2 ] for q = 9. 1
1, 91, 7462, 605242, 49031983, 3971657053, 321704819164, 26058095733124, 2110705802810605, 170967170463507055, 13848340811466703906, 1121715605764106708446, 90858964067210376612667, 7359576089446900104682897 (list; graph; refs; listen; history; text; internal format)
OFFSET
2,2
LINKS
FORMULA
G.f.: 1/[(1-x)(1-9x)(1-81x)].
a(n) = Product_{i=1..2} (9^(n-i+1)-1)/(9^i-1), by definition. - Vincenzo Librandi, Aug 04 2016
MATHEMATICA
Table[QBinomial[n, 2, 9], {n, 2, 20}] (* Vincenzo Librandi, Aug 04 2016 *)
PROG
(Sage) [gaussian_binomial(n, 2, 9) for n in range(2, 16)] # Zerinvary Lajos, May 28 2009
(Magma) r:=2; q:=9; [&*[(1-q^(n-i+1))/(1-q^i): i in [1..r]]: n in [r..20]]; // Vincenzo Librandi, Aug 04 2016
CROSSREFS
Sequence in context: A238541 A217853 A210461 * A172174 A060078 A202564
KEYWORD
nonn
AUTHOR
EXTENSIONS
Offset changed by Vincenzo Librandi, Aug 04 2016
STATUS
approved

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Last modified March 1 22:23 EST 2024. Contains 370443 sequences. (Running on oeis4.)