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A344415
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Numbers whose greatest prime index is half their sum of prime indices.
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19
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4, 9, 12, 25, 30, 40, 49, 63, 70, 84, 112, 121, 154, 165, 169, 198, 220, 264, 273, 286, 289, 325, 351, 352, 361, 364, 390, 442, 468, 520, 529, 561, 595, 624, 646, 714, 741, 748, 765, 832, 841, 850, 874, 918, 931, 952, 961, 988, 1020, 1045, 1173, 1197, 1224
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OFFSET
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1,1
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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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FORMULA
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EXAMPLE
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The sequence of terms together with their prime indices begins:
4: {1,1} 198: {1,2,2,5}
9: {2,2} 220: {1,1,3,5}
12: {1,1,2} 264: {1,1,1,2,5}
25: {3,3} 273: {2,4,6}
30: {1,2,3} 286: {1,5,6}
40: {1,1,1,3} 289: {7,7}
49: {4,4} 325: {3,3,6}
63: {2,2,4} 351: {2,2,2,6}
70: {1,3,4} 352: {1,1,1,1,1,5}
84: {1,1,2,4} 361: {8,8}
112: {1,1,1,1,4} 364: {1,1,4,6}
121: {5,5} 390: {1,2,3,6}
154: {1,4,5} 442: {1,6,7}
165: {2,3,5} 468: {1,1,2,2,6}
169: {6,6} 520: {1,1,1,3,6}
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MATHEMATICA
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primeMS[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];
Select[Range[100], Max[primeMS[#]]==Total[primeMS[#]]/2&]
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CROSSREFS
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The partitions with these Heinz numbers are counted by A035363.
A001222 counts prime factors with multiplicity.
A301987 lists numbers whose sum of prime indices equals their product.
A334201 adds up all prime indices except the greatest.
Cf. A000070, A001414, A209816, A301988, A316413, A316428, A320924, A325037, A325038, A325044, A330950, A344293, A344294, A344297.
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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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