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 A268882 Number of n X 4 binary arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two exactly once. 1
 5, 54, 501, 4133, 31956, 236960, 1706732, 12034000, 83485488, 571836176, 3876692480, 26059576704, 173934499008, 1153927868416, 7615733792000, 50035609197824, 327432063642624, 2135189929320448, 13880060602788864 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 16*a(n-1) - 88*a(n-2) + 200*a(n-3) - 208*a(n-4) + 96*a(n-5) - 16*a(n-6) for n>7. Empirical g.f.: x*(5 - 26*x + 77*x^2 - 131*x^3 + 156*x^4 - 80*x^5 + 4*x^6) / (1 - 8*x + 12*x^2 - 4*x^3)^2. - Colin Barker, Jan 15 2019 EXAMPLE Some solutions for n=4: ..1..0..1..0. .0..1..0..1. .0..0..0..1. .0..0..0..0. .0..1..0..0 ..1..0..1..0. .0..0..0..0. .0..1..0..1. .0..1..1..0. .1..0..1..0 ..0..0..1..0. .0..0..0..1. .0..0..0..1. .0..0..0..0. .0..0..0..1 ..0..1..0..0. .0..0..1..0. .1..0..1..0. .1..0..1..0. .0..0..0..0 CROSSREFS Column 4 of A268886. Sequence in context: A208429 A275353 A221544 * A229298 A087125 A110430 Adjacent sequences:  A268879 A268880 A268881 * A268883 A268884 A268885 KEYWORD nonn AUTHOR R. H. Hardin, Feb 15 2016 STATUS approved

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Last modified November 29 18:41 EST 2021. Contains 349416 sequences. (Running on oeis4.)