A158515 Number of colors needed to paint a wheel graph on n nodes.

0, 1, 2, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4

Offset

0,3

Comments

Adjacent nodes are not allowed to have the same color.

Links

Antti Karttunen, Table of n, a(n) for n = 0..1001

Eric Weisstein's World of Mathematics, Wheel Graph

Wikipedia, Wheel graph

Index entries for linear recurrences with constant coefficients, signature (0, 1).

Formula

G.f.: x*(1+2*x+2*x^2+2*x^3)/(1-x^2)

Prog

(PARI) a(n)=if(n<4, n, 4-n%2)
(Scheme) (define (A158515 n) (if (< n 4) n (- 4 (modulo n 2)))) ;; Antti Karttunen, Sep 14 2017

Crossrefs

Cf. A158411, A158478.

Sequence in context: A182101 A242289 A349229 * A285884 A123709 A165482

Adjacent sequences: A158512 A158513 A158514 * A158516 A158517 A158518

Keyword

nonn

Author

Jaume Oliver Lafont, Mar 20 2009

Status

approved