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Search: id:A137258
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| A137258 |
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Primes p that satisfy s-t < 0 where s=sigma(2*p+1) mod phi(p) and t=sigma(2*p+1) mod p. |
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+0
1
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| 3, 5, 7, 17, 19, 139, 157, 577, 1201, 27361, 530401, 2513281
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The function sigma(.) is the sum of positive divisors function and the funtion phi(.) is the Euler phi-function
The positive values of s-t for primes p<2000 are 0, 2, 3, 4.
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CROSSREFS
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Adjacent sequences: A137255 A137256 A137257 this_sequence A137259 A137260 A137261
Sequence in context: A062547 A125739 A122853 this_sequence A053341 A086086 A141772
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KEYWORD
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nonn,more
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AUTHOR
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Juan Lopez Gonzalez (juan.lopezg(AT)estudiante.uam.es), Apr 25 2008
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EXTENSIONS
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a(10)-a(12) added by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 23 2008
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