0,3

Adjacent nodes are not allowed to have the same color.

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

Eric Weisstein's World of Mathematics, Wheel graph

Wikipedia, Wheel graph

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

(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

Cf. A158411, A158478.

Sequence in context: A139048 A182101 A242289 * A285884 A123709 A165482

Adjacent sequences: A158512 A158513 A158514 * A158516 A158517 A158518

nonn

Jaume Oliver Lafont, Mar 20 2009

approved