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 A297426 Number of n X 3 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 2 neighboring 1s. 1
 1, 7, 14, 22, 68, 163, 320, 782, 1889, 4109, 9474, 22365, 50630, 115709, 268817, 616265, 1410697, 3253586, 7480630, 17161490, 39477589, 90787636, 208528864, 479338273, 1102090695, 2532624372, 5820869563, 13380882748, 30754476169 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = a(n-1) + 7*a(n-3) + a(n-5) - 4*a(n-6). Empirical g.f.: x*(1 + 6*x + 7*x^2 + x^3 - 3*x^4 - 4*x^5) / (1 - x - 7*x^3 - x^5 + 4*x^6). - Colin Barker, Feb 28 2019 EXAMPLE Some solutions for n=5: ..0..1..0. .1..1..1. .1..1..0. .1..1..1. .0..1..0. .0..1..1. .1..1..1 ..1..1..1. .0..1..0. .0..1..1. .0..1..0. .1..1..1. .0..1..1. .0..1..0 ..0..0..0. .0..0..0. .0..0..0. .0..1..0. .0..0..0. .0..0..0. .0..0..0 ..0..1..1. .0..1..1. .0..1..1. .1..0..1. .1..1..1. .0..1..1. .1..1..1 ..0..1..1. .0..1..1. .0..1..1. .0..1..0. .0..1..0. .1..1..0. .0..1..0 CROSSREFS Column 3 of A297431. Sequence in context: A190367 A246172 A366112 * A036556 A013644 A178894 Adjacent sequences: A297423 A297424 A297425 * A297427 A297428 A297429 KEYWORD nonn AUTHOR R. H. Hardin, Dec 30 2017 STATUS approved

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Last modified September 12 04:22 EDT 2024. Contains 375842 sequences. (Running on oeis4.)