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A145793 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only either four adjacent vertically or four adjacent horizontally. 0
1, 1, 1, 1, 1, 2, 3, 5, 8, 17, 40, 108, 294, 944, 3040, 12114, 49757, 243775, 1210271, 7153531, 43484383, 316861269, 2366046579, 21108349931, 192219307524, 2092034177623, 23326966046445, 311290850669433, 4251413939111348 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

Table of n, a(n) for n=1..29.

CROSSREFS

Sequence in context: A123612 A077177 A303874 * A113879 A205303 A025071

Adjacent sequences:  A145790 A145791 A145792 * A145794 A145795 A145796

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 19 2008

STATUS

approved

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Last modified July 22 10:03 EDT 2019. Contains 325219 sequences. (Running on oeis4.)