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Search: id:A118369
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| A118369 |
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Numbers n such that prod_{d|n} d + 1 is prime. |
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+0
2
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| 1, 2, 6, 10, 14, 24, 26, 54, 56, 74, 88, 94, 134, 146, 154, 174, 206, 238, 248, 266, 296, 314, 326, 328, 374, 378, 386, 430, 442, 466, 472, 488, 494, 498, 510, 568, 582, 584, 634, 674, 680, 710, 730, 742, 786, 856, 874, 894, 918, 962, 986, 1038, 1094, 1174
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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See A118370 for the corresponding primes, 'divisorial primes'.
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EXAMPLE
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The (positive) divisors of 6 are 1,2,3,6. As 6*3*2*1 + 1 = 37 is prime, 6 is a term.
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PROGRAM
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(PARI) for(n=1, 2500, s=1; fordiv(n, d, s=s*d); if(isprime(s+1), print1(n, ", ")))
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CROSSREFS
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Cf. A118370, A007955.
Sequence in context: A103747 A000952 A039956 this_sequence A082816 A074105 A133931
Adjacent sequences: A118366 A118367 A118368 this_sequence A118370 A118371 A118372
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KEYWORD
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nonn
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AUTHOR
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Rick L. Shepherd (rshepherd2(AT)hotmail.com), Apr 25 2006
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