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 A186460 Number of (n+1) X 8 binary arrays with every 2 X 2 subblock commuting with each of its horizontal and vertical 2 X 2 subblock neighbors. 1
 245, 292, 590, 945, 1681, 2377, 4121, 5633, 8893, 11977, 19037, 27133, 43249, 63485, 98801, 146333, 225061, 336241, 513933, 771609, 1174525, 1768605, 2685617, 4051469, 6143169, 9277789, 14055269, 21241521, 32162333, 48626537, 73602781 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 7 of A186462. LINKS R. H. Hardin, Table of n, a(n) for n = 1..200 FORMULA Empirical: a(n) = 2*a(n-1) - 2*a(n-3) + 2*a(n-4) - a(n-5) for n>13. Empirical g.f.: x*(245 - 198*x + 6*x^2 + 255*x^3 - 115*x^4 - 144*x^5 + 369*x^6 - 547*x^7 - 36*x^8 - 640*x^9 + 484*x^10 - 300*x^11 + 784*x^12) / ((1 - x)*(1 - x - x^2 + x^3 - x^4)). - Colin Barker, Apr 18 2018 EXAMPLE Some solutions for 3 X 8: ..0..1..0..0..0..0..0..1....1..0..0..0..1..0..1..0....1..0..0..0..0..0..0..0 ..1..0..1..0..0..0..0..0....1..0..0..0..0..1..0..1....1..0..0..0..0..0..0..0 ..0..1..0..1..0..0..0..0....1..0..0..0..0..0..1..0....1..0..0..0..0..0..0..0 CROSSREFS Cf. A186462. Sequence in context: A233821 A216233 A157246 * A171994 A129210 A137521 Adjacent sequences: A186457 A186458 A186459 * A186461 A186462 A186463 KEYWORD nonn AUTHOR R. H. Hardin, Feb 22 2011 STATUS approved

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Last modified May 28 01:34 EDT 2024. Contains 372900 sequences. (Running on oeis4.)