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 A223688 Petersen graph (8,2) coloring a rectangular array: number of n X 4 0..15 arrays where 0..15 label nodes of a graph with edges 0,1 0,8 8,14 8,10 1,2 1,9 9,15 9,11 2,3 2,10 10,12 3,4 3,11 11,13 4,5 4,12 12,14 5,6 5,13 13,15 6,7 6,14 7,0 7,15 and every array movement to a horizontal or antidiagonal neighbor moves along an edge of this graph. 1
 432, 12384, 363600, 10817856, 324280368, 9762152544, 294583794768, 8901308553408, 269168305340592, 8142829402619232, 246392700317804880, 7456528028109531456, 225671563725028735536, 6830216796989608170336 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 4 of A223692. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 59*a(n-1) - 1103*a(n-2) + 7621*a(n-3) - 16900*a(n-4). Empirical g.f.: 144*x*(3 - 91*x + 760*x^2 - 1856*x^3) / (1 - 59*x + 1103*x^2 - 7621*x^3 + 16900*x^4). - Colin Barker, Aug 22 2018 EXAMPLE Some solutions for n=3: ..6.14..6.14....0..8.10..2....4..5..4..3....6..7.15.13....2.10.12.14 ..6.14..6..7...10..2.10..8....4..3.11.13...15..9.11..3...12.14..8..0 ..6..7.15..9...10..8.10..2...11..9.15..7...15.13.11..9....8.10..8.14 CROSSREFS Cf. A223692. Sequence in context: A223436 A230922 A109123 * A269183 A228105 A232905 Adjacent sequences:  A223685 A223686 A223687 * A223689 A223690 A223691 KEYWORD nonn AUTHOR R. H. Hardin, Mar 25 2013 STATUS approved

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Last modified July 22 05:47 EDT 2019. Contains 325213 sequences. (Running on oeis4.)