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A228731
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Number of independent subsets in the rooted tree with Matula-Goebel number n that contain the root.
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3
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1, 1, 2, 1, 3, 2, 4, 1, 4, 3, 5, 2, 6, 4, 6, 1, 5, 4, 8, 3, 8, 5, 9, 2, 9, 6, 8, 4, 10, 6, 8, 1, 10, 5, 12, 4, 12, 8, 12, 3, 8, 8, 10, 5, 12, 9, 15, 2, 16, 9, 10, 6, 16, 8, 15, 4, 16, 10, 9, 6, 18, 8, 16, 1, 18, 10, 9, 5, 18, 12, 20, 4, 15, 12, 18, 8, 20, 12
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OFFSET
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1,3
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COMMENTS
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this sequence and A228732 are defined by a pair of mutually recursive functions, see A184165 for definition (called b and c there).
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LINKS
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FORMULA
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MATHEMATICA
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r[n_] := FactorInteger[n][[1, 1]];
s[n_] := n/r[n];
A[n_] := A[n] = If[n==1, {1, 1}, If[PrimeOmega[n]==1, {A[PrimePi[n]][[2]], A[PrimePi[n]] // Total}, A[r[n]] * A[s[n]]]];
a[n_] := A[n][[1]];
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PROG
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CROSSREFS
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KEYWORD
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nonn,mult
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AUTHOR
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STATUS
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approved
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