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A145863
Number of n X n binary arrays symmetric under 90-degree rotation with all ones connected only in two by two blocks.
0
1, 2, 1, 2, 2, 7, 7, 22, 24, 108, 150, 786, 1301, 8045, 15509, 116985, 273970, 2472105, 6959192, 74864863, 250693524, 3242639202, 13050355068, 202176993015, 975396539666, 18089511084508, 104443510575847, 2322049495419469
OFFSET
1,2
EXAMPLE
Maximal 7 X 7 example:
0 0 0 0 0 0 0
0 1 1 0 1 1 0
0 1 1 0 1 1 0
0 0 0 0 0 0 0
0 1 1 0 1 1 0
0 1 1 0 1 1 0
0 0 0 0 0 0 0
CROSSREFS
Sequence in context: A093655 A023140 A145859 * A240492 A110775 A229232
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 22 2008
STATUS
approved