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A340448
Radio number of the cycle graph C_n.
0
0, 1, 2, 4, 4, 7, 9, 13, 12, 17, 20, 26, 24, 31, 35, 43, 40, 49, 54, 64, 60, 71, 77, 89, 84, 97, 104, 118, 112, 127, 135, 151, 144, 161, 170, 188, 180, 199, 209, 229, 220, 241, 252, 274, 264, 287, 299, 323
OFFSET
1,3
COMMENTS
Extended to a(1) using the formula.
LINKS
Eric Weisstein's World of Mathematics, Cycle Graph
Eric Weisstein's World of Mathematics, Radio Number
FORMULA
a(n) = (n - 2)/2 floor(n/4) + n - 1 for mod(n, 2) = 0.
a(n) = (n + 3) (n - 1)/8 for mod(n, 4) = 1.
a(n) = (n - 1)/2 (floor(n/4) + 2) for mod(n, 2) = 1.
G.f.: x^2*(-1-x-2*x^2-x^4+x^7) / ( (1+x)^2*(x^2+1)^2*(x-1)^3 ). - R. J. Mathar, Jun 02 2022
MATHEMATICA
Table[Piecewise[{{(n - 2)/2 Floor[n/4] + n - 1, Mod[n, 2] == 0}, {(n + 3) (n - 1)/8, Mod[n, 4] == 1}, {(n - 1)/2 (Floor[n/4] + 2), Mod[n, 2] == 1}}], {n, 20}]
CROSSREFS
Sequence in context: A325723 A353927 A262884 * A241387 A284612 A070072
KEYWORD
nonn,easy
AUTHOR
Eric W. Weisstein, Jan 07 2021
STATUS
approved