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Search: id:A063451
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| A063451 |
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n * sigma(n)-1 is a prime. |
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+0
1
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| 2, 3, 5, 6, 10, 11, 13, 15, 18, 19, 20, 24, 26, 28, 31, 33, 41, 50, 51, 53, 56, 59, 60, 63, 70, 76, 78, 80, 82, 83, 86, 89, 90, 93, 95, 99, 101, 102, 103, 104, 111, 116, 122, 123, 131, 132, 142, 143, 144, 145, 146, 148, 149, 150, 152, 153, 154, 155, 156, 161, 163
(list; graph; listen)
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OFFSET
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1,1
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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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PROGRAM
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(PARI) j=[]; for(n=1, 350, if(isprime(n*sigma(n)-1), j=concat(j, n))); j
(PARI) { n=0; for (m=1, 10^9, if (isprime(m*sigma(m) - 1), write("b063451.txt", n++, " ", m); if (n==1000, break)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Aug 21 2009]
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CROSSREFS
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Sequence in context: A034044 A047447 A094739 this_sequence A076474 A057760 A074243
Adjacent sequences: A063448 A063449 A063450 this_sequence A063452 A063453 A063454
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KEYWORD
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easy,nonn
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AUTHOR
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Jason Earls (zevi_35711(AT)yahoo.com), Jul 25 2001
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