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A325363
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Heinz numbers of integer partitions into nonzero triangular numbers A000217.
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1
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1, 2, 4, 5, 8, 10, 13, 16, 20, 25, 26, 29, 32, 40, 47, 50, 52, 58, 64, 65, 73, 80, 94, 100, 104, 107, 116, 125, 128, 130, 145, 146, 151, 160, 169, 188, 197, 200, 208, 214, 232, 235, 250, 256, 257, 260, 290, 292, 302, 317, 320, 325, 338, 365, 376, 377, 394, 397
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OFFSET
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1,2
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COMMENTS
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The Heinz number of an integer partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k).
The enumeration of these partitions by sum is given by A007294.
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LINKS
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EXAMPLE
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The sequence of terms together with their prime indices begins:
1: {}
2: {1}
4: {1,1}
5: {3}
8: {1,1,1}
10: {1,3}
13: {6}
16: {1,1,1,1}
20: {1,1,3}
25: {3,3}
26: {1,6}
29: {10}
32: {1,1,1,1,1}
40: {1,1,1,3}
47: {15}
50: {1,3,3}
52: {1,1,6}
58: {1,10}
64: {1,1,1,1,1,1}
65: {3,6}
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MATHEMATICA
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nn=1000;
primeMS[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];
trgs=Table[n*(n+1)/2, {n, Sqrt[2*PrimePi[nn]]}];
Select[Range[nn], SubsetQ[trgs, primeMS[#]]&]
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CROSSREFS
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Cf. A000217, A007294, A056239, A112798, A240026, A325327, A325360, A325362, A325367, A325390, A325394, A325400.
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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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