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A157959 Number of n-colorings of the Desargues graph. 2
0, 0, 2, 42258, 217727724, 120716639420, 15509657482350, 784759781145102, 21017383336908728, 355260899699333784, 4240584584018848890, 38562180170120230250, 281853103175962977252, 1722023964356731913748, 9058240485370625897894, 41970560739174197375910 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

The Desargues graph is a cubic symmetric distance-regular graph with 20 vertices and 30 edges.

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..1000

Eric Weisstein's World of Mathematics, "Desargues Graph".

Eric Weisstein's World of Mathematics, "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.

FORMULA

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.

MAPLE

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);

CROSSREFS

Sequence in context: A055578 A232733 A106025 * A290047 A094213 A321382

Adjacent sequences:  A157956 A157957 A157958 * A157960 A157961 A157962

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Mar 10 2009

STATUS

approved

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Last modified June 18 22:37 EDT 2021. Contains 345125 sequences. (Running on oeis4.)