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Search: id:A159191
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| A159191 |
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Number of n-colorings of the Robertson graph. |
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+0
1
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| 0, 0, 0, 24, 3490848, 3501104400, 564523119840, 31643453033640, 886834653776064, 15220684846368288, 181298924180884800, 1627952400490177080, 11672280987833510880, 69664869701930893104
(list; graph; listen)
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OFFSET
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0,4
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COMMENT
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The Robertson graph is a quartic graph on 19 vertices and 38 edges.
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LINKS
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Weisstein, Eric W. "Robertson Graph".
Weisstein, Eric W. "Chromatic Polynomial".
Timme, Marc; van Bussel, Frank; Fliegner, Denny; Stolzenberg, Sebastian (2009) "Counting complex disordered states by efficient pattern matching: chromatic polynomials and Potts partition functions", New J. Phys. 11 023001, doi: 10.1088/1367-2630/11/2/023001.
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FORMULA
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a(n) = n^19 -38*n^18 + ... (see Maple program).
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MAPLE
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a:= n-> n^19 -38*n^18 +703*n^17 -8436*n^16 +73761*n^15 -500004*n^14 +2727105*n^13 -12246808*n^12 +45913333*n^11 -144701057*n^10 +383839223*n^9 -853388854*n^8 +1574465385*n^7 -2370057775*n^6 +2835163369*n^5 -2587310804*n^4 +1685281636*n^3 -693467820*n^2 +134217080*n: seq (a(n), n=0..20);
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CROSSREFS
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Sequence in context: A028371 A013774 A088020 this_sequence A013820 A075406 A075404
Adjacent sequences: A159188 A159189 A159190 this_sequence A159192 A159193 A159194
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KEYWORD
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nonn
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AUTHOR
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Alois P. Heinz (heinz(AT)hs-heilbronn.de), Apr 05 2009
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