A066407 Number of orthogonal arrays OA(6,n,2,1).

0, 0, 2880, 109440, 2753280, 60249600, 1249274880, 25351280640, 509998510080, 10223941017600, 204671339642880, 4094969962659840, 81911756682362880, 1638334041381273600, 32767472282735738880, 655355778068620247040, 13107166223775883591680, 262143729787114723737600

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