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Search: id:A065512
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| A065512 |
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Numbers n such that sigma(n) + 1 is prime. |
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+0
1
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| 1, 3, 5, 6, 10, 11, 12, 17, 20, 22, 24, 26, 27, 29, 30, 38, 41, 42, 45, 46, 51, 55, 59, 62, 68, 69, 71, 77, 82, 85, 88, 91, 99, 101, 104, 105, 106, 107, 108, 114, 116, 118, 125, 126, 132, 135, 136, 137, 140, 141, 145, 146, 147, 149, 150, 155, 158, 160, 161
(list; graph; listen)
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OFFSET
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1,2
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LINKS
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Harry J. Smith, Table of n, a(n) for n=1,...,1000
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EXAMPLE
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sigma(10) + 1 = 18 + 1 = 19 (prime). sigma(24) + 1 = 60 + 1 = 61 (prime).
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MATHEMATICA
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Select[ Range[170], PrimeQ[ DivisorSigma[1, # ] + 1] & ]
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PROGRAM
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(PARI) { n=0; for (m=1, 10^9, if (isprime(sigma(m) + 1), write("b065512.txt", n++, " ", m); if (n==1000, return)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Oct 20 2009]
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CROSSREFS
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Cf. A000203.
Sequence in context: A102606 A102372 A095829 this_sequence A066147 A140951 A065873
Adjacent sequences: A065509 A065510 A065511 this_sequence A065513 A065514 A065515
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KEYWORD
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nonn
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AUTHOR
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Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Nov 26 2001
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