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A324748
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Number of strict integer partitions of n containing all prime indices of the parts.
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10
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1, 1, 0, 1, 0, 1, 1, 1, 0, 2, 1, 2, 3, 2, 2, 4, 3, 4, 3, 5, 6, 9, 8, 7, 8, 11, 12, 13, 15, 17, 22, 22, 20, 28, 31, 32, 36, 41, 43, 53, 53, 59, 70, 76, 77, 89, 99, 108, 124, 135, 139, 160, 172, 188, 209, 229, 243, 274, 298, 315, 353, 391, 417, 457, 496, 538, 588
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OFFSET
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0,10
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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 first 15 terms count the following integer partitions.
1: (1)
3: (2,1)
5: (4,1)
6: (3,2,1)
7: (4,2,1)
9: (8,1)
9: (6,2,1)
10: (4,3,2,1)
11: (8,2,1)
11: (5,3,2,1)
12: (9,2,1)
12: (7,4,1)
12: (6,3,2,1)
13: (8,4,1)
13: (6,4,2,1)
14: (8,3,2,1)
14: (7,4,2,1)
15: (12,2,1)
15: (9,3,2,1)
15: (8,4,2,1)
15: (5,4,3,2,1)
An example for n = 6 is (20,18,11,5,3,2,1), with prime indices:
20: {1,1,3}
18: {1,2,2}
11: {5}
5: {3}
3: {2}
2: {1}
1: {}
All of these prime indices {1,2,3,5} belong to the partition, as required.
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MATHEMATICA
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Table[Length[Select[IntegerPartitions[n], UnsameQ@@#&&SubsetQ[#, PrimePi/@First/@Join@@FactorInteger/@DeleteCases[#, 1]]&]], {n, 0, 30}]
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CROSSREFS
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Cf. A000720, A001462, A007097, A074971, A078374, A112798, A276625, A279861, A290689, A290760, A305713.
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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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