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 A251214 Number of (n+1) X (3+1) 0..1 arrays with no 2 X 2 subblock having zero or two 1s. 1
 49, 191, 758, 3089, 12503, 50912, 206715, 840931, 3417338, 13896689, 56488843, 229680232, 933724343, 3796257055, 15433585490, 62747204885, 255100769239, 1037135769960, 4216531992291, 17142642411675, 69694499491242 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 2*a(n-1) + 17*a(n-2) - 20*a(n-3) - 85*a(n-4) + 68*a(n-5) + 146*a(n-6) - 84*a(n-7) - 56*a(n-8) + 24*a(n-9). Empirical g.f.: x*(49 + 93*x - 457*x^2 - 694*x^3 + 1424*x^4 + 1456*x^5 - 1592*x^6 - 692*x^7 + 384*x^8) / (1 - 2*x - 17*x^2 + 20*x^3 + 85*x^4 - 68*x^5 - 146*x^6 + 84*x^7 + 56*x^8 - 24*x^9). - Colin Barker, Nov 27 2018 EXAMPLE Some solutions for n=4: ..1..1..1..1....1..1..1..1....1..0..1..1....0..1..0..1....0..0..1..0 ..1..0..1..0....0..1..1..0....1..1..1..1....0..0..0..0....1..0..0..0 ..1..1..1..1....1..1..0..0....1..1..0..1....1..0..1..0....1..1..0..1 ..1..0..1..0....0..1..1..0....0..1..1..1....1..1..1..1....1..1..1..1 ..1..1..1..1....1..1..1..1....1..1..1..1....0..1..1..1....1..0..1..1 CROSSREFS Column 3 of A251219. Sequence in context: A244182 A244183 A244184 * A158638 A198386 A351663 Adjacent sequences: A251211 A251212 A251213 * A251215 A251216 A251217 KEYWORD nonn AUTHOR R. H. Hardin, Nov 30 2014 STATUS approved

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Last modified March 31 06:14 EDT 2023. Contains 361634 sequences. (Running on oeis4.)