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A141440
Number of n X n integer matrices, symmetric under horizontal reflection, with adjacent elements differing by no more than 1, counting matrices differing by a constant only once.
1
1, 3, 121, 771, 317259, 4380445, 18838482047, 567241901289, 25690815631493191, 1691995329032459285, 809857047207692689731131, 116848319343974137914103093, 592161880926391194661929563951461
OFFSET
1,2
LINKS
R. H. Hardin, Aug 06 2008, Table of n, a(n) for n = 1..18
CROSSREFS
Sequence in context: A202768 A289986 A301559 * A156001 A229633 A171357
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 06 2008
STATUS
approved