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A055194
Number of 3 X n binary matrices with distinct rows, up to row and column permutation; (n,3)-hypergraphs (including empty hyperedge but excluding multiple hyperedges).
1
3, 16, 52, 134, 302, 614, 1159, 2064, 3504, 5716, 9018, 13818, 20643, 30158, 43190, 60758, 84110, 114746, 154469, 205422, 270132, 351562, 453172, 578962, 733551, 922238, 1151072, 1426932, 1757618, 2151920, 2619731, 3172138, 3821524, 4581682, 5467942, 6497272, 7688431
OFFSET
2,1
FORMULA
G.f.: -x^2*(x^8-2*x^6-2*x^5+4*x^3-4*x-3)/((x^3-1)^2*(x^2-1)^2*(x-1)^4).
a(n) ~ n^7/30240. - Stefano Spezia, Nov 22 2023
CROSSREFS
Cf. A002727.
Sequence in context: A089363 A000574 A041233 * A190730 A173052 A027540
KEYWORD
easy,nonn
AUTHOR
Vladeta Jovovic, Jun 30 2000
EXTENSIONS
More terms from James A. Sellers, Jul 04 2000
a(35)-a(38) from Stefano Spezia, Nov 22 2023
STATUS
approved