A158347 Number of n-colorings of the Walther Graph.

0, 0, 2, 4033920, 159894687204, 301280127057920, 100770286250343750, 11334165274707633792, 603801344040208577480, 18674487128527060598784, 382076301190534627489290, 5650667805968496542000000, 64331764646611255469788332, 590498122988857695000330240

Offset

0,3

Comments

The Walther Graph has 25 vertices and 31 edges.

Links

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

Marc Timme, Frank van Bussel, Denny Fliegner, and Sebastian Stolzenberg, Counting complex disordered states by efficient pattern matching: chromatic polynomials and Potts partition functions, New J. Phys. 11 023001, 2009.

Eric Weisstein's World of Mathematics, Walther Graphs.

Eric Weisstein's World of Mathematics, Chromatic Polynomial.

Index entries for linear recurrences with constant coefficients, signature (26, -325, 2600, -14950, 65780, -230230, 657800, -1562275, 3124550, -5311735, 7726160, -9657700, 10400600, -9657700, 7726160, -5311735, 3124550, -1562275, 657800, -230230, 65780, -14950, 2600, -325, 26, -1).

Formula

a(n) = n^25 -31*n^24 + ... (see Maple program).

Maple

a:= n-> n^25 -31*n^24 +465*n^23 -4494*n^22 +31437*n^21 -169528*n^20 +732875*n^19 -2607473*n^18 +7777403*n^17 -19708162*n^16 +42836515*n^15 -80400727*n^14 +130882589*n^13 -185209067*n^12 +227870356*n^11 -243267982*n^10 +224314530*n^9 -177255496*n^8 +118586759*n^7 -65961560*n^6 +29694659*n^5 -10386912*n^4 +2643810*n^3 -434456*n^2 +34489*n:
seq(a(n), n=0..20);

Crossrefs

Sequence in context: A337368 A137601 A232962 * A273354 A352126 A157991

Adjacent sequences: A158344 A158345 A158346 * A158348 A158349 A158350

Keyword

nonn,easy

Author

Alois P. Heinz, Mar 16 2009

Status

approved