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A062514
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Sigma(phi(n)) is a prime.
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2
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3, 4, 5, 6, 8, 10, 12, 17, 32, 34, 40, 48, 60, 85, 128, 136, 160, 170, 192, 204, 240, 4369, 8192, 8224, 8704, 8738, 10240, 10280, 10880, 12288, 12336, 13056, 15360, 15420, 16320, 65537, 131072, 131074, 131584, 139264, 139808, 163840, 164480, 174080
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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LINKS
| Harry J. Smith, Table of n, a(n) for n=1,...,73
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EXAMPLE
| Phi(174080)=65536. Sigma(65536)= 131071, a prime.
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PROG
| (PARI) je=[]; for(n=1, 300000, s=sigma(eulerphi(n)); if(isprime(s), je=concat(je, n))); je
(PARI) { n=0; for (m=1, 10^9, if(isprime(sigma(eulerphi(m))), write("b062514.txt", n++, " ", m); if (n==73, break)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Aug 08 2009]
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CROSSREFS
| Sequence in context: A120162 A002859 A180646 * A065875 A197639 A167057
Adjacent sequences: A062511 A062512 A062513 * A062515 A062516 A062517
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KEYWORD
| easy,nonn
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AUTHOR
| Jason Earls (zevi_35711(AT)yahoo.com), Jul 09 2001
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