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A320700
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Odd numbers whose product of prime indices is a nonprime prime power (A246547).
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2
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7, 9, 19, 21, 23, 25, 27, 49, 53, 57, 63, 81, 97, 103, 115, 121, 125, 131, 133, 147, 159, 171, 189, 227, 243, 289, 311, 343, 361, 371, 393, 399, 419, 441, 477, 513, 515, 529, 567, 575, 625, 661, 691, 719, 729, 917, 931, 933, 961, 1007, 1009, 1029, 1067, 1083
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OFFSET
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1,1
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LINKS
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EXAMPLE
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The sequence of all integer partitions whose Heinz numbers belong to the sequence begins: (4), (2,2), (8), (4,2), (9), (3,3), (2,2,2), (4,4), (16), (8,2), (4,2,2), (2,2,2,2), (25), (27), (9,3), (5,5), (3,3,3), (32), (8,4), (4,4,2), (16,2), (8,2,2), (4,2,2,2), (49), (2,2,2,2,2)
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MATHEMATICA
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Select[Range[1000], With[{x=Times@@Cases[FactorInteger[#], {p_, k_}:>PrimePi[p]^k]}, OddQ[#]&&!PrimeQ[x]&&PrimePowerQ[x]]&]
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CROSSREFS
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Cf. A000720, A000961, A001597, A003963, A056239, A064573, A112798, A246547, A279787, A320322, A320325, A320698, A320699.
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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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