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A290612
Number of maximal independent vertex sets (and minimal vertex covers) in the n-wheel graph.
0
4, 3, 6, 6, 8, 11, 13, 18, 23, 30, 40, 52, 69, 91, 120, 159, 210, 278, 368, 487, 645, 854, 1131, 1498, 1984, 2628, 3481, 4611, 6108, 8091, 10718, 14198, 18808, 24915, 33005, 43722, 57919, 76726, 101640, 134644, 178365, 236283, 313008, 414647, 549290, 727654, 963936
OFFSET
4,1
LINKS
Eric Weisstein's World of Mathematics, Maximal Independent Vertex Set
Eric Weisstein's World of Mathematics, Minimal Vertex Cover
Eric Weisstein's World of Mathematics, Wheel Graph
FORMULA
a(n) = a(n-1) + a(n-2) - a(n-4).
G.f.: (x^3 (4 - x - x^2 - 3 x^3))/(1 - x - x^2 + x^4).
MATHEMATICA
Table[1 + RootSum[-1 - # + #^3 &, #^(n - 1) &], {n, 4, 20}]
LinearRecurrence[{1, 1, 0, -1}, {4, 3, 6, 6, 8}, 20]
CoefficientList[Series[(4 - x - x^2 - 3 x^3)/(1 - x - x^2 + x^4), {x, 0, 20}], x]
CROSSREFS
Sequence in context: A362449 A021233 A352922 * A292616 A071901 A266576
KEYWORD
nonn
AUTHOR
Eric W. Weisstein, Aug 07 2017
STATUS
approved