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 A185553 1/3 the number of nX3 0..2 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors 1
 1, 26, 224, 2530, 25496, 269496, 2792166, 29168100, 303674928, 3165976954, 32988466864, 343808442136, 3582861328974, 37338788146540, 389120024162368, 4055176375558754, 42260513291812936, 440413129026231448 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Column 3 of A185559 LINKS R. H. Hardin, Table of n, a(n) for n = 1..200 FORMULA Empirical: a(n)=7*a(n-1)+41*a(n-2)-44*a(n-3)-111*a(n-4)-140*a(n-5)+291*a(n-6)-225*a(n-7)+511*a(n-8)+2150*a(n-9)-3007*a(n-10)-6248*a(n-11)-624*a(n-12)+19900*a(n-13)-14308*a(n-14)+15248*a(n-15)-13312*a(n-16)-1648*a(n-17)+21440*a(n-18)-5632*a(n-19)-3968*a(n-20)+5632*a(n-21)-14336*a(n-22)-8192*a(n-23) EXAMPLE Some solutions for 4X3 with a(1,1)=0 ..0..0..0....0..1..1....0..0..2....0..1..1....0..0..0....0..2..0....0..1..1 ..1..1..1....0..0..1....2..2..2....0..1..1....1..2..2....0..2..0....0..0..1 ..0..0..1....2..0..1....2..1..1....2..0..2....1..2..0....0..0..2....2..1..0 ..0..1..1....2..2..1....0..0..1....2..0..2....2..2..0....2..2..2....2..1..0 CROSSREFS Sequence in context: A242262 A241938 A317865 * A269658 A220714 A159519 Adjacent sequences:  A185550 A185551 A185552 * A185554 A185555 A185556 KEYWORD nonn AUTHOR R. H. Hardin Jan 31 2011 STATUS approved

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Last modified December 1 22:12 EST 2021. Contains 349435 sequences. (Running on oeis4.)