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Search: id:A071311
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| A071311 |
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Squarefree numbers n with largest prime factor = floor(sqrt(n)). |
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+0
1
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| 30, 182, 195, 399, 870, 1023, 1406, 1443, 1722, 2915, 3782, 4623, 5402, 7055, 8099, 10302, 10815, 11990, 12099, 12882, 12995, 16383, 17423, 18906, 19599, 24806, 24963, 26895, 30102, 32942, 33123, 37442, 37635, 39999, 44943, 52670, 52899
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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If n = p(1)*p(2)*...p(r) is in the sequence, where p(r) is the largest prime factor, then p(1)*p(2)*...*p(r-1) - p(r) = 1 or 2
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EXAMPLE
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1023 = 3.11.31 and sqrt(1023)=31.98437... hence 1023 is in the sequence
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PROGRAM
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(PARI) for(n=2, 100000, if(issquarefree(n)*component(component(factor(n), 1), omega(n))==floor(sqrt(n)), print1(n, ", ")))
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CROSSREFS
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Cf. A071835.
Sequence in context: A042756 A156318 A042758 this_sequence A120339 A064247 A125340
Adjacent sequences: A071308 A071309 A071310 this_sequence A071312 A071313 A071314
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KEYWORD
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easy,nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Jun 11 2002
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