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A067965
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Number of binary arrangements without adjacent 1's on n X n array connected ne-sw and nw-se.
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12
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2, 9, 119, 2704, 177073, 21836929, 6985036032, 4576976735769, 7263963336910751, 24830487842030082304, 198126078679714777857441, 3494153303407491549112098721, 141264727800378056245286463971328, 12779122891585386852029424628087941481, 2628141044813862018744988536642011269669959
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OFFSET
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1,1
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LINKS
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Vaclav Kotesovec, Table of n, a(n) for n = 1..16
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EXAMPLE
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Neighbors for n=4 (dots represent spaces):
. o..o..o..o
...\/ \/ \/
.../\ /\ /\
. o..o..o..o
...\/ \/ \/
.../\ /\ /\
. o..o..o..o
...\/ \/ \/
.../\ /\ /\
. o..o..o..o
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CROSSREFS
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Cf. circle A000204, line A000045, arrays: e-w ne-sw nw-se A067963, n-s nw-se A067964, e-w n-s nw-se A066864, e-w ne-sw n-s nw-se A063443, n-s A067966, e-w n-s A006506, nw-se A067962, toruses: bare A002416, ne-sw nw-se A067960, ne-sw n-s nw-se A067959, e-w ne-sw n-s nw-se A067958, n-s A067961, e-w n-s A027683, e-w ne-sw n-s A066866.
Sequence in context: A006126 A201381 A075538 * A194017 A135543 A088862
Adjacent sequences: A067962 A067963 A067964 * A067966 A067967 A067968
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KEYWORD
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nonn,hard
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AUTHOR
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R. H. Hardin, Feb 02 2002
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EXTENSIONS
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Term a(14) from Vaclav Kotesovec, Dec 06 2011
Term a(15) from Vaclav Kotesovec, Jan 03 2012
Term a(16) from Vaclav Kotesovec, May 01 2012
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STATUS
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approved
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