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Search: id:A164788
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| A164788 |
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Numbers such that the sum of the distinct prime factors is a cube. |
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+0
2
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| 1, 15, 45, 75, 183, 225, 285, 295, 354, 357, 375, 405, 429, 510, 549, 583, 675, 708, 799, 855, 910, 943
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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This is the 3rd row of the infinite array A(k,n) = n-th positive integer such that the sum of the distinct prime factors is of the form j^k for integers j, k. The 2nd row is A164722.
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FORMULA
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{n such that A008472(n) = k^3 for k an integer}. {n such that A008472(n) is in A000578}.
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EXAMPLE
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a(2) = 15 because 15 = 3 * 5, the sum of distinct prime factors being 3+5 = 8 = 2^3. a(5) = 183 = 3 * 61 because 3 + 61 = 64 = 4^3. a(7) = 285 because 285 = 3 * 5 * 19 and 3 + 5 + 19 = 27 = 3^3.
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CROSSREFS
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Cf. A000578, A008472, A164722.
Sequence in context: A084821 A066763 A033849 this_sequence A060536 A014634 A126228
Adjacent sequences: A164785 A164786 A164787 this_sequence A164789 A164790 A164791
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KEYWORD
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easy,more,nonn
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AUTHOR
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Jonathan Vos Post (jvospost3(AT)gmail.com), Aug 26 2009
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