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A158525
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Number of connected spanning subgraphs and number of forests of the wheel graph W_n.
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0
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38, 134, 462, 1582, 5406, 18462, 63038, 215230, 734846, 2508926, 8566014, 29246206, 99852798, 340918782, 1163969534, 3974040574, 13568223230, 46324811774, 158162800638, 540001579006, 1843680714750, 6294719700990
(list; graph; refs; listen; history; internal format)
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OFFSET
| 4,1
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COMMENTS
| The wheel graph W_n has n vertices and 2n-2 edges. A single vertex is connected to all vertices of an (n-1)-cycle.
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LINKS
| Weisstein, Eric W. "Wheel graph".
Wikipedia "Wheel graph".
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FORMULA
| G.f.: (38-56*x+20*x^2)*x^4 / (6*x^2+1-5*x-2*x^3).
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MAPLE
| a:= n-> `if` (n<4, 0, (Matrix([[5, 1, 0], [ -6, 0, 1], [2, 0, 0]])^n)[3, 2]): seq (a(n), n=4..30);
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CROSSREFS
| Sequence in context: A044670 A118633 A004076 * A044370 A044751 A164093
Adjacent sequences: A158522 A158523 A158524 * A158526 A158527 A158528
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KEYWORD
| nonn
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AUTHOR
| Alois P. Heinz (heinz(AT)hs-heilbronn.de), Mar 20 2009
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