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 A231957 T(n,k)=Number of (n+1)X(k+1) 0..1 arrays with every element equal to some horizontal, vertical, diagonal or antidiagonal neighbor, with top left element zero 9
 4, 18, 18, 64, 142, 64, 236, 1034, 1034, 236, 888, 7756, 14842, 7756, 888, 3336, 58350, 220472, 220472, 58350, 3336, 12512, 438540, 3292876, 6517534, 3292876, 438540, 12512, 46928, 3295580, 49124582, 193955142, 193955142, 49124582, 3295580, 46928 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Table starts ......4.........18............64..............236.................888 .....18........142..........1034.............7756...............58350 .....64.......1034.........14842...........220472.............3292876 ....236.......7756........220472..........6517534...........193955142 ....888......58350.......3292876........193955142.........11501370840 ...3336.....438540......49124582.......5764579644........681107245458 ..12512....3295580.....732691918.....171279257338......40322931224352 ..46928...24766738...10928482748....5089308419738....2387295795105696 .176032..186126146..163005613290..151223178459482..141340282653200376 .660320.1398767358.2431334781688.4493424899719612.8368067905547685676 LINKS R. H. Hardin, Table of n, a(n) for n = 1..287 FORMULA Empirical for column k: k=1: a(n) = 4*a(n-1) -2*a(n-2) +4*a(n-3) k=2: a(n) = 7*a(n-1) +2*a(n-2) +13*a(n-3) +8*a(n-4) k=3: [order 12] k=4: [order 26] k=5: [order 50] EXAMPLE Some solutions for n=3 k=4 ..0..1..1..0..0....0..1..1..0..0....0..0..1..1..0....0..0..0..1..0 ..0..0..0..0..1....0..1..1..0..0....0..0..0..0..0....0..0..0..1..0 ..0..0..1..1..1....1..0..0..0..1....1..0..1..0..0....1..0..0..1..0 ..1..1..0..0..0....0..1..1..1..1....0..1..1..1..1....0..1..1..1..0 CROSSREFS Sequence in context: A070923 A064220 A205105 * A275952 A081420 A039277 Adjacent sequences:  A231954 A231955 A231956 * A231958 A231959 A231960 KEYWORD nonn,tabl AUTHOR R. H. Hardin, Nov 15 2013 STATUS approved

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Last modified June 14 05:51 EDT 2021. Contains 345018 sequences. (Running on oeis4.)