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 A301842 Number of 2Xn 0..1 arrays with every element equal to 0, 1 or 2 horizontally or antidiagonally adjacent elements, with upper left element zero. 2
 2, 8, 25, 81, 263, 855, 2778, 9027, 29333, 95316, 309725, 1006437, 3270370, 10626915, 34531665, 112209036, 364618033, 1184809305, 3849982618, 12510339087, 40651763813, 132096011916, 429239834325, 1394794836717, 4532320816850 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Row 2 of A301841. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 3*a(n-1) +a(n-2) -2*a(n-4) for n>6 EXAMPLE Some solutions for n=5 ..0..1..1..0..0. .0..0..1..0..0. .0..0..0..1..1. .0..1..0..1..1 ..0..0..1..0..0. .0..0..0..1..1. .1..0..1..0..0. .1..1..0..0..0 CROSSREFS Cf. A301841. Sequence in context: A037560 A138804 A212323 * A240478 A288539 A281338 Adjacent sequences:  A301839 A301840 A301841 * A301843 A301844 A301845 KEYWORD nonn AUTHOR R. H. Hardin, Mar 27 2018 STATUS approved

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Last modified January 27 21:28 EST 2022. Contains 350654 sequences. (Running on oeis4.)