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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
J.-Z. Zhang, Z.-S. You and Z.-L. Li, Enumeration of binary orthogonal arrays of strength 1, Discrete Math., 239 (2000), 191-198.
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
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.)