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 A209807 Number of (n+1) X 2 0..3 arrays with every 2 X 2 subblock having two distinct values, and new values 0..3 introduced in row major order. 1
 7, 34, 173, 930, 5193, 29782, 173789, 1025274, 6089457, 36315262, 217102757, 1299807138, 7788836985, 46697385574, 280057392749, 1679892321738, 10077743984769, 60460730002126, 362743958401973, 2176391017766514 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 1 of A209814. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 8*a(n-1) - 7*a(n-2) - 28*a(n-3) - 12*a(n-4). Empirical g.f.: x*(7 - 22*x - 50*x^2 - 20*x^3) / ((1 + x)*(1 - 6*x)*(1 - 3*x - 2*x^2)). - Colin Barker, Jul 13 2018 EXAMPLE Some solutions for n=4: ..0..0....0..0....0..0....0..1....0..0....0..0....0..0....0..1....0..0....0..0 ..0..1....0..1....1..1....0..0....0..1....0..1....1..0....1..0....0..1....0..1 ..1..0....0..1....0..1....0..1....0..0....0..0....0..1....0..1....0..1....1..1 ..0..0....0..0....1..0....1..0....0..1....1..0....1..0....1..0....1..0....0..1 ..2..2....0..1....0..0....0..0....1..1....1..0....0..1....0..0....0..1....0..0 CROSSREFS Cf. A209814. Sequence in context: A055271 A209890 A027209 * A080048 A177140 A027233 Adjacent sequences:  A209804 A209805 A209806 * A209808 A209809 A209810 KEYWORD nonn AUTHOR R. H. Hardin, Mar 13 2012 STATUS approved

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Last modified October 23 11:19 EDT 2019. Contains 328345 sequences. (Running on oeis4.)