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Search: id:A133466
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| A133466 |
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Positive integers n for which there is exactly one integer i in {1,2,3,...,n-1} such that i*n is a square. |
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+0
1
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| 4, 8, 12, 20, 24, 28, 40, 44, 52, 56, 60, 68, 76, 84, 88, 92, 104, 116, 120, 124, 132, 136, 140, 148, 152, 156, 164, 168, 172, 184, 188, 204, 212, 220, 228, 232, 236, 244, 248, 260, 264, 268, 276, 280, 284, 292, 296, 308, 312, 316, 328, 332, 340, 344, 348, 356
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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It appears that all terms of this sequence are exactly four times those of the square-free integers (A005117).
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EXAMPLE
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4 is in the sequence because among the products 1*4,2*4,3*4 = 4,8,12 there is exactly one square.
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CROSSREFS
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Cf. A005117.
Sequence in context: A145203 A045750 A026042 this_sequence A037168 A033691 A090658
Adjacent sequences: A133463 A133464 A133465 this_sequence A133467 A133468 A133469
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KEYWORD
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nonn
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AUTHOR
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John W. Layman (layman(AT)math.vt.edu), Nov 28 2007
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