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A048885
Number of nonisomorphic orthogonal arrays OA(4n,4n-1,2,2).
4
1, 1, 1, 5, 3, 130, 7570, 355293682
OFFSET
1,4
COMMENTS
Equivalently, number of 3-(4*n,2*n,n-1) designs.
REFERENCES
A. S. Hedayat, N. J. A. Sloane and J. Stufken, Orthogonal Arrays, Springer-Verlag, NY, 1999, see Table 7.37 page 165.
CROSSREFS
Cf. A007299.
Sequence in context: A343582 A267512 A230389 * A264738 A002208 A100653
KEYWORD
nonn,nice,hard,more
EXTENSIONS
a(7) computed by N. J. A. Sloane
a(8) from Brendan McKay, Feb 11 2012
STATUS
approved