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%I #15 Jun 30 2023 00:45:45
%S 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,
%T 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,
%U 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
%N Number of colors needed to paint a wheel graph on n nodes.
%C Adjacent nodes are not allowed to have the same color.
%H Antti Karttunen, <a href="/A158515/b158515.txt">Table of n, a(n) for n = 0..1001</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/WheelGraph.html">Wheel Graph</a>
%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Wheel_graph">Wheel graph</a>
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0, 1).
%F G.f.: x*(1+2*x+2*x^2+2*x^3)/(1-x^2)
%o (PARI) a(n)=if(n<4,n,4-n%2)
%o (Scheme) (define (A158515 n) (if (< n 4) n (- 4 (modulo n 2)))) ;; _Antti Karttunen_, Sep 14 2017
%Y Cf. A158411, A158478.
%K nonn
%O 0,3
%A _Jaume Oliver Lafont_, Mar 20 2009
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