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 A297396 Number of 3 X n 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1 neighboring 1. 1
 1, 9, 19, 37, 127, 323, 763, 2121, 5557, 14031, 37065, 97027, 250371, 653707, 1706245, 4431885, 11544027, 30085525, 78290135, 203852347, 530958219, 1382353401, 3599332477, 9373032927, 24405570561, 63547912011, 165475162027, 430875964651 (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) + a(n-2) + 8*a(n-3) + a(n-4) - 2*a(n-6). Empirical g.f.: x*(1 + 8*x + 9*x^2 + x^3 - 2*x^4 - 2*x^5) / (1 - x - x^2 - 8*x^3 - x^4 + 2*x^6). - Colin Barker, Feb 28 2019 EXAMPLE Some solutions for n=5: ..0..0..0..1..1. .0..1..1..0..0. .0..0..0..1..0. .1..0..0..0..0 ..1..1..0..0..0. .0..0..0..0..0. .0..0..0..0..1. .0..1..0..0..0 ..0..0..0..1..1. .0..0..0..1..1. .0..0..0..0..0. .0..0..0..1..1 CROSSREFS Row 3 of A297395. Sequence in context: A195042 A157034 A198590 * A145958 A290245 A039299 Adjacent sequences: A297393 A297394 A297395 * A297397 A297398 A297399 KEYWORD nonn AUTHOR R. H. Hardin, Dec 29 2017 STATUS approved

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Last modified December 4 23:46 EST 2022. Contains 358572 sequences. (Running on oeis4.)