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A339886
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Numbers whose prime indices cover an interval of positive integers starting with 2.
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5
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1, 3, 9, 15, 27, 45, 75, 81, 105, 135, 225, 243, 315, 375, 405, 525, 675, 729, 735, 945, 1125, 1155, 1215, 1575, 1875, 2025, 2187, 2205, 2625, 2835, 3375, 3465, 3645, 3675, 4725, 5145, 5625, 5775, 6075, 6561, 6615, 7875, 8085, 8505, 9375, 10125, 10395, 10935
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OFFSET
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1,2
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COMMENTS
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A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798.
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LINKS
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EXAMPLE
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The sequence of terms together with their prime indices begins:
3: {2}
9: {2,2}
15: {2,3}
27: {2,2,2}
45: {2,2,3}
75: {2,3,3}
81: {2,2,2,2}
105: {2,3,4}
135: {2,2,2,3}
225: {2,2,3,3}
243: {2,2,2,2,2}
315: {2,2,3,4}
375: {2,3,3,3}
405: {2,2,2,2,3}
525: {2,3,3,4}
675: {2,2,2,3,3}
729: {2,2,2,2,2,2}
735: {2,3,4,4}
945: {2,2,2,3,4}
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MATHEMATICA
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primeMS[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];
normQ[m_]:=Or[m=={}, Union[m]==Range[Max[m]]];
Select[Range[100], normQ[primeMS[#]-1]&]
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CROSSREFS
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The version starting at 1 is A055932.
The partitions with these Heinz numbers are counted by A264396.
A000009 counts partitions covering an initial interval.
A000070 counts partitions with a selected part.
A016945 lists numbers with smallest prime index 2.
A034296 counts gap-free (or flat) partitions.
A073491 lists numbers with gap-free prime indices.
A325240 lists numbers with smallest prime multiplicity 2.
Cf. A001223, A001522, A006128, A007052, A124010, A257989, A257993, A264401, A317090, A317589, A339737.
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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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