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 A269109 T(n,k)=Number of nXk 0..3 arrays with some element plus some horizontally or vertically adjacent neighbor totalling three no more than once. 8
 4, 16, 16, 60, 180, 60, 216, 1740, 1740, 216, 756, 15540, 40908, 15540, 756, 2592, 132300, 872460, 872460, 132300, 2592, 8748, 1090740, 17593092, 43964700, 17593092, 1090740, 8748, 29160, 8787660, 342055548, 2085484068, 2085484068 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Table starts ......4.........16.............60................216....................756 .....16........180...........1740..............15540.................132300 .....60.......1740..........40908.............872460...............17593092 ....216......15540.........872460...........43964700.............2085484068 ....756.....132300.......17593092.........2085484068...........232068730044 ...2592....1090740......342055548........95166487524.........24808345933548 ...8748....8787660.....6482020140......4227147007836.......2579398703502996 ..29160...69580980...120520189980....184069947098892.....262780733311913580 ..96228..543538380..2208175854948...7894012975085748...26357371124964908460 .314928.4200069300.39988864047276.334480929126425748.2611360040338484328156 LINKS R. H. Hardin, Table of n, a(n) for n = 1..264 FORMULA Empirical for column k: k=1: a(n) = 6*a(n-1) -9*a(n-2) k=2: a(n) = 14*a(n-1) -49*a(n-2) for n>3 k=3: a(n) = 36*a(n-1) -378*a(n-2) +972*a(n-3) -729*a(n-4) for n>5 k=4: [order 6] for n>7 k=5: [order 14] for n>15 k=6: [order 26] for n>27 k=7: [order 64] for n>65 EXAMPLE Some solutions for n=3 k=4 ..0..0..1..2. .0..2..2..0. .0..1..1..1. .0..2..3..1. .2..0..1..0 ..0..2..3..3. .0..2..0..1. .0..0..3..1. .0..0..1..3. .0..0..1..1 ..1..3..1..3. .1..0..0..2. .0..2..2..3. .0..0..0..2. .2..2..2..3 CROSSREFS Column 1 is A120926(n+1). Sequence in context: A207535 A269194 A269143 * A269201 A269289 A267933 Adjacent sequences:  A269106 A269107 A269108 * A269110 A269111 A269112 KEYWORD nonn,tabl AUTHOR R. H. Hardin, Feb 19 2016 STATUS approved

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Last modified May 28 03:04 EDT 2020. Contains 334671 sequences. (Running on oeis4.)