OFFSET
5,2
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 = 5..200
FORMULA
G.f.: x^5/((1-x)*(1-5*x)*(1-25*x)*(1-125*x)*(1-625*x)*(1-3125*x)). - Vincenzo Librandi, Aug 10 2016
a(n) = Product_{i=1..5} (5^(n-i+1)-1)/(5^i-1), by definition. - Vincenzo Librandi, Aug 10 2016
MATHEMATICA
QBinomial[Range[5, 15], 5, 5] (* Harvey P. Dale, Oct 05 2011 *)
Table[QBinomial[n, 5, 5], {n, 5, 20}] (* Vincenzo Librandi, Aug 10 2016 *)
PROG
(Sage) [gaussian_binomial(n, 5, 5) for n in range(5, 14)] # Zerinvary Lajos, May 27 2009
(Magma) r:=5; q:=5; [&*[(1-q^(n-i+1))/(1-q^i): i in [1..r]]: n in [r..20]]; // Vincenzo Librandi, Aug 10 2016
(PARI) r=5; q=5; for(n=r, 30, print1(prod(j=1, r, (1-q^(n-j+1))/(1-q^j)), ", ")) \\ G. C. Greubel, Jun 04 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
Offset changed by Vincenzo Librandi, Aug 10 2016
STATUS
approved