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 A186466 Number of (n+1) X 4 0..2 arrays with every 2 X 2 subblock commuting with each of its horizontal and vertical 2 X 2 subblock neighbors. 1
 277, 243, 942, 1203, 3190, 4023, 9982, 13985, 32390, 48553, 105436, 165842, 344498, 562526, 1130820, 1898670, 3724364, 6385226, 12298364, 21417538, 40692652, 71701562, 134848628, 239701634, 447381180, 800490426, 1485546884, 2671168754 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 3 of A186472. LINKS R. H. Hardin, Table of n, a(n) for n = 1..200 FORMULA Empirical: a(n) = 2*a(n-1) + a(n-2) - 4*a(n-3) + 4*a(n-4) - 2*a(n-5) for n>12. Empirical g.f.: x*(277 - 311*x + 179*x^2 + 184*x^3 - 294*x^4 - 210*x^5 + 276*x^6 - 170*x^7 + 176*x^8 + 4*x^9 - 2*x^10 + x^11) / ((1 - x)*(1 - x - 2*x^2 + 2*x^3 - 2*x^4)). - Colin Barker, Apr 18 2018 EXAMPLE Some solutions for 3 X 4: ..1..0..1..0....0..0..0..0....1..2..0..1....0..0..0..0....1..0..0..0 ..0..1..0..1....1..0..0..0....2..0..2..0....0..0..0..0....0..1..0..0 ..2..0..1..2....0..1..0..0....0..2..0..2....1..0..0..2....1..0..1..1 CROSSREFS Cf. A186472. Sequence in context: A169976 A297755 A166192 * A045022 A108253 A108255 Adjacent sequences: A186463 A186464 A186465 * A186467 A186468 A186469 KEYWORD nonn AUTHOR R. H. Hardin, Feb 22 2011 STATUS approved

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Last modified March 30 19:10 EDT 2023. Contains 361622 sequences. (Running on oeis4.)