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A130145 Number of nonisomorphic orthogonal arrays OA(n,4,2,2)'s when n is not a multiple of 8. 0
1, 3, 7, 15, 28, 48, 79, 123, 184, 268, 379, 523, 709, 943, 1234, 1594, 2032, 2560, 3194, 3946, 4832, 5872, 7082, 8482, 10097 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Annals of Statistics 2007, Vol. 35, No. 2, 793-814; from the abstract: [...]. In this paper, we provide a complete solution to enumerating nonisomorphic two-level orthogonal arrays of strength d with d+2 constraints for any d and any run size n = lambda(2^d). Our results not only give the number of nonisomorphic orthogonal arrays for given $d$ and $n$, but also provide a systematic way of explicitly constructing these arrays. [...].

LINKS

Table of n, a(n) for n=1..25.

John Stufken and Boxin Tang, Complete enumeration of two-Level orthogonal arrays of strength d with d+2 constraints

FORMULA

Empirical g.f.: x / ((x-1)^6*(x+1)*(x^2+x+1)^2). - Colin Barker, Aug 01 2013

CROSSREFS

Sequence in context: A025587 A101498 A027965 * A023552 A293316 A009859

Adjacent sequences:  A130142 A130143 A130144 * A130146 A130147 A130148

KEYWORD

nonn,more

AUTHOR

Jonathan Vos Post, Aug 15 2007

STATUS

approved

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Last modified February 21 12:10 EST 2018. Contains 299411 sequences. (Running on oeis4.)