

A121816


Conjectured chromatic number of the square of an outerplanar graph G^2 as a function of the maximum degree of a vertex of G.


0



9, 10, 11, 12, 13, 14, 16, 17, 19, 20, 22, 23, 25, 26, 28, 29, 31, 32, 34, 35, 37, 38, 40, 41, 43, 44, 46, 47, 49, 50, 52, 53, 55, 56, 58, 59, 61, 62, 64, 65, 67, 68, 70, 71, 73, 74, 76, 77, 79, 80, 82, 83, 85, 86, 88, 89, 91, 92, 94, 95, 97, 98, 100
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OFFSET

4,1


LINKS



FORMULA

a(n) = n + 5 if 4 <= n <= 7; a(n) = floor(3*n/2) + 1 if n >= 8.
a(n) = (3+(1)^n+6*n)/4 for n>7. a(n) = a(n1)+a(n2)a(n3). G.f.: x^4*(x^68*x^2+x+9) / ((x1)^2*(x+1)).  Colin Barker, Apr 30 2013


CROSSREFS



KEYWORD

nonn,easy


AUTHOR



STATUS

approved



