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A291441
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Matula-Goebel numbers of orderless same-trees with all leaves equal to 1.
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12
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1, 4, 8, 16, 32, 49, 64, 128, 256, 343, 361, 512, 1024, 2048, 2401, 2809, 4096, 6859, 8192, 12031, 16384, 16807, 17161, 32768, 51529, 65536, 96721, 117649, 130321, 131072, 148877, 262144, 516961, 524288, 637643, 718099, 757907, 823543, 1048576, 2097152, 2248091
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OFFSET
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1,2
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COMMENTS
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See A289078 for the definition of orderless same-tree.
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LINKS
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EXAMPLE
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a(20)=12031 corresponds to the following same-tree: {{1,1,1,1},{{1,1},{1,1}}}.
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MATHEMATICA
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nn=200000;
primeMS[n_]:=If[n===1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];
leafcount[n_]:=If[n===1, 1, With[{m=primeMS[n]}, If[Length[m]===1, leafcount[First[m]], Total[leafcount/@m]]]];
sameQ[n_]:=Or[n===1, With[{m=primeMS[n]}, And[Length[m]>1, SameQ@@leafcount/@m, And@@sameQ/@m]]];
Select[Range[nn], sameQ]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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