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A298303
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Matula-Goebel numbers of rooted trees with thinning limbs.
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4
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1, 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26, 27, 28, 30, 31, 32, 33, 35, 36, 39, 40, 42, 44, 45, 46, 48, 49, 50, 52, 54, 55, 56, 58, 60, 62, 63, 64, 65, 66, 69, 70, 72, 75, 76, 77, 78, 80, 81, 84, 86, 87, 88, 90, 91, 92, 93, 94
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OFFSET
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1,2
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COMMENTS
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An unlabeled rooted tree has thinning limbs if its outdegrees are weakly decreasing from root to leaves.
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LINKS
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MATHEMATICA
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MGtree[n_]:=If[n===1, {}, MGtree/@Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];
thinQ[t_]:=And@@Cases[t, b_List:>Length[b]>=Max@@Length/@b, {0, Infinity}];
Select[Range[200], thinQ[MGtree[#]]&]
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CROSSREFS
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Cf. A000081, A007097, A061775, A111299, A124343, A124346, A214577, A276625, A290760, A291636, A298126, A298120, A298304, A298305.
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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