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 A240513 Number of n X 2 0..1 arrays with no element equal to exactly two horizontal and vertical neighbors, with new values 0..1 introduced in row major order. 23
 2, 3, 6, 10, 21, 42, 86, 179, 370, 770, 1601, 3330, 6930, 14419, 30006, 62442, 129941, 270410, 562726, 1171043, 2436962, 5071362, 10553601, 21962242, 45703842, 95110563, 197926886, 411889610, 857150101, 1783745642, 3712008566, 7724760339 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 2 of A240519. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 2*a(n-1) + a(n-2) - a(n-3) - 2*a(n-4) + a(n-5). Empirical g.f.: x*(2 - x)*(1 - x^2 - 2*x^3) / ((1 - x)*(1 - x - 2*x^2 - x^3 + x^4)). - Colin Barker, Feb 24 2018 Empirical: a(n) = 1+A105309(n). - R. J. Mathar, Nov 09 2018 EXAMPLE All solutions for n=4: ..0..1....0..1....0..1....0..1....0..0....0..1....0..1....0..1....0..1....0..1 ..0..0....0..1....1..0....0..1....1..1....1..0....1..1....1..0....1..0....1..0 ..0..1....1..0....1..1....1..0....0..0....1..0....0..1....0..1....0..0....0..1 ..1..0....1..0....1..0....0..1....1..1....0..1....1..0....1..0....1..0....0..1 CROSSREFS Cf. A240519. Sequence in context: A211180 A265582 A242563 * A036650 A049889 A014270 Adjacent sequences:  A240510 A240511 A240512 * A240514 A240515 A240516 KEYWORD nonn AUTHOR R. H. Hardin, Apr 06 2014 STATUS approved

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Last modified January 20 09:55 EST 2022. Contains 350471 sequences. (Running on oeis4.)