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 A223218 T(n,k)=3X3X3 triangular graph coloring a rectangular array: number of nXk 0..5 arrays where 0..5 label nodes of a graph with edges 0,1 0,2 1,2 1,3 1,4 2,4 3,4 2,5 4,5 and every array movement to a horizontal or vertical neighbor moves along an edge of this graph 9
 6, 18, 18, 60, 126, 60, 192, 918, 918, 192, 624, 6642, 15498, 6642, 624, 2016, 48114, 254694, 254694, 48114, 2016, 6528, 348462, 4232586, 9640008, 4232586, 348462, 6528, 21120, 2523798, 70014654, 367156350, 367156350, 70014654, 2523798, 21120 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Table starts ......6........18............60...............192...................624 .....18.......126...........918..............6642.................48114 .....60.......918.........15498............254694...............4232586 ....192......6642........254694...........9640008.............367156350 ....624.....48114.......4232586.........367156350...........32213930742 ...2016....348462......70014654.......13964418774.........2819203560630 ...6528...2523798....1160465118......531419938920.......247143798101322 ..21120..18278946...19217863458....20220127602030.....21653415762483246 ..68352.132387858..318374151654...769404277676466...1897735773641654046 .221184.958837662.5273531868834.29276398278326448.166300121937966179310 LINKS R. H. Hardin, Table of n, a(n) for n = 1..220 FORMULA Empirical for column k: k=1: a(n) = 2*a(n-1) +4*a(n-2) k=2: a(n) = 6*a(n-1) +9*a(n-2) k=3: [order 8] k=4: [order 15] k=5: [order 45] k=6: [order 77] EXAMPLE Some solutions for n=3 k=4 ..0..1..0..1....0..1..2..5....4..3..1..2....0..2..1..4....0..1..4..1 ..1..4..1..4....1..2..5..4....3..4..2..1....1..4..2..1....1..0..1..4 ..2..1..2..5....4..1..4..5....4..3..1..4....0..2..1..2....4..2..4..5 CROSSREFS Sequence in context: A074390 A255617 A253771 * A045857 A074791 A093106 Adjacent sequences:  A223215 A223216 A223217 * A223219 A223220 A223221 KEYWORD nonn,tabl AUTHOR R. H. Hardin Mar 18 2013 STATUS approved

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Last modified October 17 10:50 EDT 2017. Contains 293469 sequences.