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 A207170 Number of 2Xn 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 1 0 1 vertically 18
 4, 16, 36, 81, 169, 361, 784, 1681, 3600, 7744, 16641, 35721, 76729, 164836, 354025, 760384, 1633284, 3508129, 7535025, 16184529, 34762816, 74666881, 160376896, 344473600, 739894401, 1589218225, 3413480625, 7331811876, 15747991081 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Row 2 of A207169 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = a(n-1) +a(n-2) +3*a(n-3) +a(n-4) -a(n-5) -a(n-6) for n>7 G.f: 4*x -x^2*(-16-20*x-29*x^2-4*x^3+13*x^4+9*x^5) / ( (x^3+2*x^2+x-1)*(x^3-x^2-1) ). - R. J. Mathar, Aug 10 2017 Empirical: 31*a(n) = 114*A002478(n) +133*A002478(n-1) +55*A002478(n) +10*A077961(n) +32*A077961(n-1) -24*A077961(n-2) for n>1. - R. J. Mathar, Nov 09 2018 EXAMPLE Some solutions for n=4 ..1..1..1..1....1..0..0..1....0..1..1..0....1..1..1..1....1..0..0..1 ..0..1..1..1....1..0..0..1....0..1..1..0....1..1..1..1....1..1..1..1 CROSSREFS Sequence in context: A085040 A030179 A207025 * A207069 A207436 A189145 Adjacent sequences: A207167 A207168 A207169 * A207171 A207172 A207173 KEYWORD nonn AUTHOR R. H. Hardin Feb 15 2012 STATUS approved

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Last modified December 3 11:24 EST 2022. Contains 358517 sequences. (Running on oeis4.)