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A067959 Number of binary arrangements without adjacent 1's on n X n torus connected ne-sw n-s nw-se. 8
1, 7, 22, 547, 9021, 812830, 70046159, 24082448515, 10363980496342, 14228018243052057, 29400555005986658803, 166705587265151114516638, 1606507128309318588452521527 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..13.

V. Kotesovec, Non-attacking chess pieces, 6ed, 2013, p. 73.

EXAMPLE

Neighbors for n=4 (dots represent spaces):

.\|/\|/\|/\|/

. o..o..o..o

./|\/|\/|\/|\

.\|/\|/\|/\|/

. o..o..o..o

./|\/|\/|\/|\

.\|/\|/\|/\|/

. o..o..o..o

./|\/|\/|\/|\

.\|/\|/\|/\|/

. o..o..o..o

./|\/|\/|\/|\

CROSSREFS

Cf. circle A000204, line A000045, arrays: ne-sw nw-se A067965, 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, 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: A197991 A197853 A087184 * A273216 A070411 A167224

Adjacent sequences:  A067956 A067957 A067958 * A067960 A067961 A067962

KEYWORD

nonn,hard

AUTHOR

R. H. Hardin, Feb 02 2002

EXTENSIONS

a(13) from Vaclav Kotesovec, Aug 22 2016

STATUS

approved

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Last modified February 24 09:40 EST 2020. Contains 332209 sequences. (Running on oeis4.)