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 A251148 Number of (n+1) X (7+1) 0..2 arrays with every 2 X 2 subblock summing to 4 and no 2 X 2 subblock having exactly two nonzero entries. 1
 853, 1075, 1413, 1987, 2925, 4491, 7101, 11491, 18917, 31587, 53389, 91275, 157789, 275843, 487717, 872259, 1577901, 2886539, 5337725, 9971363, 18803813, 35765155, 68549453, 132276107, 256749085, 500872771, 981317541, 1929582211, 3805684077 (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) = 3*a(n-1) - 5*a(n-3) + a(n-4) + 2*a(n-5). Empirical g.f.: x*(853 - 1484*x - 1812*x^2 + 2013*x^3 + 1486*x^4) / ((1 - x)*(1 + x)*(1 - 2*x)*(1 - x - x^2)). - Colin Barker, Nov 26 2018 EXAMPLE Some solutions for n=4: ..1..0..1..1..1..1..2..1....2..0..2..0..1..0..1..1....0..1..1..0..1..2..1..1 ..2..1..2..0..2..0..1..0....1..1..1..1..2..1..2..0....2..1..1..2..1..0..1..1 ..1..0..1..1..1..1..2..1....2..0..2..0..1..0..1..1....0..1..1..0..1..2..1..1 ..1..2..1..1..1..1..0..1....1..1..1..1..2..1..2..0....2..1..1..2..1..0..1..1 ..1..0..1..1..1..1..2..1....2..0..2..0..1..0..1..1....0..1..1..0..1..2..1..1 CROSSREFS Column 7 of A251149. Sequence in context: A237763 A237760 A234539 * A127593 A248856 A251050 Adjacent sequences: A251145 A251146 A251147 * A251149 A251150 A251151 KEYWORD nonn AUTHOR R. H. Hardin, Nov 30 2014 STATUS approved

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Last modified December 3 01:55 EST 2023. Contains 367530 sequences. (Running on oeis4.)