A158792 Number of n-colorings of the Shrikhande graph.

0, 0, 0, 0, 240, 332400, 105480720, 7787433360, 233556076320, 3881511113760, 42569914312800, 342908176422240, 2176503575487120, 11428762115181840, 51423745096804080, 203533610650297200, 722989464927562560, 2341382980699049280, 6999973732130650560

Offset

0,5

Comments

The Shrikhande graph has 16 vertices and 48 edges.

Links

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

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.

Weisstein, Eric W. "Shrikhande Graph".

Weisstein, Eric W. "Chromatic Polynomial".

Index entries for linear recurrences with constant coefficients, signature (17, -136, 680, -2380, 6188, -12376, 19448, -24310, 24310, -19448, 12376, -6188, 2380, -680, 136, -17, 1).

Formula

a(n) = n^16 -48*n^15 + ... (see Maple program).

Maple

a:= n-> n^16 -48*n^15 +1096*n^14 -15812*n^13 +161320*n^12 -1233064*n^11 +7290402*n^10 -33903652*n^9 +124749368*n^8 -362020596*n^7 +818389712*n^6 -1407982096*n^5 +1773274371*n^4 -1531612072*n^3 +803458490*n^2 -190557420*n:
seq(a(n), n=0..20);

Crossrefs

Sequence in context: A008696 A047806 A184888 * A270051 A028678 A159950

Adjacent sequences: A158789 A158790 A158791 * A158793 A158794 A158795

Keyword

nonn,easy

Author

Alois P. Heinz, Mar 26 2009

Status

approved