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 A281559 Number of nX4 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards. 1
 0, 18, 621, 3374, 15508, 53568, 162919, 463916, 1262057, 3344312, 8682013, 22096236, 55418093, 137452378, 337368553, 820589074, 1981158104, 4751265748, 11325996647, 26856461774, 63380869317, 148929846348, 348578197271 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Column 4 of A281563. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 3*a(n-1) +7*a(n-3) -21*a(n-4) -27*a(n-5) -17*a(n-6) +84*a(n-7) +168*a(n-8) +79*a(n-9) -231*a(n-10) -480*a(n-11) -209*a(n-12) +417*a(n-13) +768*a(n-14) +266*a(n-15) -561*a(n-16) -705*a(n-17) -44*a(n-18) +468*a(n-19) +252*a(n-20) -108*a(n-21) -135*a(n-22) +27*a(n-24) for n>34 EXAMPLE Some solutions for n=4 ..0..0..0..0. .0..0..0..0. .0..1..0..1. .0..1..0..1. .0..1..0..0 ..0..1..0..1. .0..1..0..1. .1..0..0..1. .0..0..1..0. .1..1..0..0 ..0..1..0..1. .1..0..1..0. .0..1..1..0. .1..0..1..0. .0..0..1..0 ..1..0..0..1. .1..0..1..0. .1..0..1..0. .1..1..0..1. .0..1..1..0 CROSSREFS Cf. A281563. Sequence in context: A180822 A295369 A350984 * A166767 A322889 A003298 Adjacent sequences: A281556 A281557 A281558 * A281560 A281561 A281562 KEYWORD nonn AUTHOR R. H. Hardin, Jan 24 2017 STATUS approved

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Last modified December 7 14:37 EST 2023. Contains 367656 sequences. (Running on oeis4.)