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Search: id:A058540
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| A058540 |
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Another 3-way generalization of series-parallel networks with n unlabeled edges. |
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4
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| 0, 1, 3, 9, 36, 144, 651, 3015, 14634, 72654, 369063, 1904985, 9971889, 52788393, 282161025, 1520597895, 8253281871, 45075359277, 247534382298, 1365994896264, 7571065357620, 42127865408028, 235246997219400, 1317894484506336
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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Compare the combstruct construction here with those for A000084 and A058534.
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MAPLE
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spec := [ N, {N=Union(Z, S, P, Q), S=Set(Union(Z, P, Q), card>=2), P=Set(Union(Z, S, Q), card>=2), Q=Set(Union(Z, S, P), card>=2)} ]; [seq(combstruct[count](spec, size=n), n=0..40)]; # N=A058540, S=A058371
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CROSSREFS
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Cf. A000084, A058534, A058371.
Sequence in context: A125792 A057390 A106435 this_sequence A032314 A107895 A070960
Adjacent sequences: A058537 A058538 A058539 this_sequence A058541 A058542 A058543
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KEYWORD
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nonn
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AUTHOR
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njas, Dec 24 2000
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