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Search: id:A157959
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| A157959 |
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Number of n-colorings of the Desargues graph. |
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+0
1
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| 0, 0, 2, 42258, 217727724, 120716639420, 15509657482350, 784759781145102, 21017383336908728, 355260899699333784, 4240584584018848890, 38562180170120230250, 281853103175962977252, 1722023964356731913748
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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The Desargues graph is a cubic symmetric distance-regular graph with 20 vertices and 30 edges.
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LINKS
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Weisstein, Eric W. "Desargues 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^20 -30*n^19 +435*n^18 -4060*n^17 +27405*n^16 -142486*n^15 +593275*n^14 -2029770*n^13 +5806295*n^12 -14047858*n^11 +28942903*n^10 -50912200*n^9 +76328405*n^8 -96864050*n^7 +102660272*n^6 -88808037*n^5 +60384665*n^4 -30272495*n^3 +9922451*n^2 -1585121*n.
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MAPLE
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a:= n-> n^20 -30*n^19 +435*n^18 -4060*n^17 +27405*n^16 -142486*n^15 +593275*n^14 -2029770*n^13 +5806295*n^12 -14047858*n^11 +28942903*n^10 -50912200*n^9 +76328405*n^8 -96864050*n^7 +102660272*n^6 -88808037*n^5 +60384665*n^4 -30272495*n^3 +9922451*n^2 -1585121*n: seq (a(n), n=0..30);
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CROSSREFS
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Sequence in context: A001377 A055578 A106025 this_sequence A094213 A153924 A059764
Adjacent sequences: A157956 A157957 A157958 this_sequence A157960 A157961 A157962
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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), Mar 10 2009
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