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 A067964 Number of binary arrangements without adjacent 1's on n X n array connected n-s nw-se. 11
 2, 8, 90, 1876, 103484, 11462588, 3118943536, 1808994829500, 2465526600093372, 7394315828592829424, 50975951518289853305508, 784977037926751747674903856, 27509351187362150581313065415008 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Vaclav Kotesovec, Table of n, a(n) for n = 1..18 V. Kotesovec, Non-attacking chess pieces, 6ed, 2013, p. 69-71. FORMULA Limit n->infinity (a(n))^(1/n^2) = 1.503048082... (see A085850) 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, 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: A131349 A319124 A294194 * A102895 A297451 A295773 Adjacent sequences:  A067961 A067962 A067963 * A067965 A067966 A067967 KEYWORD nonn,nice,hard AUTHOR R. H. Hardin, Feb 02 2002 EXTENSIONS Terms a(14)-a(18) from Vaclav Kotesovec, May 01 2012 STATUS approved

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Last modified February 27 15:59 EST 2020. Contains 332307 sequences. (Running on oeis4.)