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A363530
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Heinz numbers of integer partitions such that 3*(sum) = (weighted sum).
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4
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1, 32, 40, 60, 100, 126, 210, 243, 294, 351, 550, 585, 770, 819, 1210, 1274, 1275, 1287, 1521, 1785, 2002, 2366, 2793, 2805, 2875, 3125, 3315, 4025, 4114, 4335, 4389, 4862, 5187, 6325, 6358, 6422, 6783, 7105, 7475, 7581, 8349, 8398, 9386, 9775, 9867, 10925
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OFFSET
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1,2
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COMMENTS
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The Heinz number of a partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k). This gives a bijective correspondence between positive integers and integer partitions.
The (one-based) weighted sum of a sequence (y_1,...,y_k) is Sum_{i=1..k} i*y_i. For example, the weighted sum of (4,2,2,1) is 1*4 + 2*2 + 3*2 + 4*1 = 18.
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LINKS
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FORMULA
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EXAMPLE
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The terms together with their prime indices begin:
1: {}
32: {1,1,1,1,1}
40: {1,1,1,3}
60: {1,1,2,3}
100: {1,1,3,3}
126: {1,2,2,4}
210: {1,2,3,4}
243: {2,2,2,2,2}
294: {1,2,4,4}
351: {2,2,2,6}
550: {1,3,3,5}
585: {2,2,3,6}
770: {1,3,4,5}
819: {2,2,4,6}
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MATHEMATICA
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prix[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];
Select[Range[1000], 3*Total[prix[#]]==Total[Accumulate[Reverse[prix[#]]]]&]
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CROSSREFS
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These partitions are counted by A363527.
A053632 counts compositions by weighted sum.
A318283 gives weighted sum of reversed prime indices, row-sums of A358136.
Cf. A000041, A000720, A001221, A046660, A106529, A118914, A124010, A181819, A215366, A359362, A359755.
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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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