0,5

The Errera graph is a planar graph on 17 vertices and 45 edges with chromatic number 4.

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, Errera Graph.

Eric Weisstein's World of Mathematics, Chromatic Polynomial.

Index entries for linear recurrences with constant coefficients, signature (18, -153, 816, -3060, 8568, -18564, 31824, -43758, 48620, -43758, 31824, -18564, 8568, -3060, 816, -153, 18, -1).

a(n) = n^17 - 45*n^16 + ... (see Maple program).

a:= n-> n^17 -45*n^16 +960*n^15 -12900*n^14 +122327*n^13 -868834*n^12 +4785355*n^11 -20863215*n^10 +72791543*n^9 -203886157*n^8 +456534224*n^7 -807157880*n^6 +1101393064*n^5 -1116652249*n^4 +788961246*n^3 -344673280*n^2 +69525840*n:

seq(a(n), n=0..20);

a[n_] := n^17 - 45*n^16 + 960*n^15 - 12900*n^14 + 122327*n^13 - 868834*n^12 + 4785355*n^11 - 20863215*n^10 + 72791543*n^9 - 203886157*n^8 + 456534224*n^7 - 807157880*n^6 + 1101393064*n^5 - 1116652249*n^4 + 788961246*n^3 - 344673280*n^2 + 69525840*n; Table[a[n], {n, 0, 10}] (* G. C. Greubel, May 29 2016 *)

Sequence in context: A282012 A378469 A147883 * A316337 A274120 A063797

Adjacent sequences: A166961 A166962 A166963 * A166965 A166966 A166967

nonn,easy

Alois P. Heinz, Oct 25 2009

approved