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 A301995 Number of nX4 0..1 arrays with every element equal to 1, 2 or 4 horizontally or antidiagonally adjacent elements, with upper left element zero. 1
 2, 8, 26, 74, 200, 530, 1394, 3656, 9578, 25082, 65672, 171938, 450146, 1178504, 3085370, 8077610, 21147464, 55364786, 144946898, 379475912, 993480842, 2600966618, 6809419016, 17827290434, 46672452290, 122190066440, 319897747034 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 4 of A301999. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 4*a(n-1) -4*a(n-2) +a(n-3) EXAMPLE Some solutions for n=5 ..0..0..1..1. .0..0..1..0. .0..0..1..1. .0..0..1..1. .0..0..1..1 ..0..0..0..0. .0..1..0..0. .1..1..0..0. .0..1..0..1. .0..1..0..0 ..1..1..1..1. .1..1..0..0. .0..0..0..0. .1..0..1..1. .1..1..0..0 ..0..0..1..1. .1..1..0..0. .0..0..1..1. .0..0..1..0. .1..1..0..0 ..0..0..1..1. .1..1..1..1. .1..1..0..0. .1..1..0..0. .1..1..1..1 CROSSREFS Cf. A301999. Sequence in context: A136594 A268502 A167826 * A325926 A097040 A302237 Adjacent sequences:  A301992 A301993 A301994 * A301996 A301997 A301998 KEYWORD nonn AUTHOR R. H. Hardin, Mar 30 2018 STATUS approved

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Last modified December 2 03:22 EST 2020. Contains 338865 sequences. (Running on oeis4.)