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A145775
Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only either two adjacent vertically or two adjacent horizontally.
0
1, 1, 1, 4, 10, 25, 98, 304, 1809, 7930, 72506, 400613, 5713422, 40142648, 888016669, 8057185631, 274304468798, 3201392865337, 169069430683773, 2534673576738596, 207045671219200314, 3988243193242437962, 504059170133969414707
OFFSET
1,4
CROSSREFS
Sequence in context: A049348 A282389 A361611 * A283958 A335637 A255718
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 18 2008
STATUS
approved