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 A066407 Number of orthogonal arrays OA(6,n,2,1). 0
 0, 0, 2880, 109440, 2753280, 60249600, 1249274880, 25351280640, 509998510080, 10223941017600, 204671339642880, 4094969962659840, 81911756682362880, 1638334041381273600, 32767472282735738880, 655355778068620247040, 13107166223775883591680, 262143729787114723737600 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Table of n, a(n) for n=1..18. J.-Z. Zhang, Z.-S. You and Z.-L. Li, Enumeration of binary orthogonal arrays of strength 1, Discrete Math., 239 (2000), 191-198. Index entries for linear recurrences with constant coefficients, signature (34,-336,1184,-1280). FORMULA a(n) = 2^n*(10^n-15*4^n+45*2^n-40). G.f.: 2880*x^3*(4*x+1) / ((2*x-1)*(4*x-1)*(8*x-1)*(20*x-1)). - Colin Barker, Aug 01 2013 CROSSREFS Sequence in context: A179703 A260369 A134856 * A184602 A144547 A259403 Adjacent sequences: A066404 A066405 A066406 * A066408 A066409 A066410 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, Dec 25 2001 EXTENSIONS More terms from Colin Barker, Aug 01 2013 STATUS approved

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Last modified May 19 03:29 EDT 2024. Contains 372666 sequences. (Running on oeis4.)