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 A297520 Number of 2 X n 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1 or 3 neighboring 1s. 1
 1, 5, 17, 33, 65, 193, 529, 1185, 2737, 7169, 18257, 43425, 104945, 264001, 656785, 1597665, 3913009, 9708161, 23980241, 58804257, 144593009, 357011905, 879991825, 2164014945, 5327178673, 13131288833, 32347250513, 79624144545, 196075443953 (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) + 4*a(n-3) + 12*a(n-4). Empirical g.f.: x*(1 + 4*x + 12*x^2 + 12*x^3) / (1 - x - 4*x^3 - 12*x^4). - Colin Barker, Mar 01 2019 EXAMPLE Some solutions for n=7: ..1..1..0..0..0..1..1. .1..0..0..0..1..1..0. .0..0..0..0..0..0..0 ..1..0..1..0..1..0..1. .0..1..0..0..1..0..1. .1..1..0..0..0..0..0 CROSSREFS Row 2 of A297519. Sequence in context: A078654 A083364 A273499 * A026394 A004538 A146231 Adjacent sequences: A297517 A297518 A297519 * A297521 A297522 A297523 KEYWORD nonn AUTHOR R. H. Hardin, Dec 31 2017 STATUS approved

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Last modified March 26 17:26 EDT 2023. Contains 361551 sequences. (Running on oeis4.)