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A065061
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Numbers n such that sigma(n) - tau(n) is a prime.
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2
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3, 8, 162, 512, 1250, 8192, 31250, 32768, 41472, 663552, 2531250, 3748322, 5120000, 6837602, 7558272, 8000000, 15780962, 33554432, 35701250, 42762752, 45334242, 68024448, 75031250, 78125000, 91125000, 137149922, 243101250, 512000000
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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MATHEMATICA
| Do[ If[ PrimeQ[ DivisorSigma[1, n] - DivisorSigma[0, n]], Print[n]], {n, 1, 10^7}]
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PROG
| (PARI) { n=0; for (m=1, 10^9, if (isprime(sigma(m) - numdiv(m)), write("b065061.txt", n++, " ", m); if (n==100, return)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Oct 05 2009]
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CROSSREFS
| I.e. A065608(n) is prime. Cf. A064205.
Sequence in context: A053605 A076147 A132563 * A007159 A081466 A092592
Adjacent sequences: A065058 A065059 A065060 * A065062 A065063 A065064
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KEYWORD
| nonn
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AUTHOR
| Jason Earls (zevi_35711(AT)yahoo.com), Nov 06 2001
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EXTENSIONS
| a(17) - a(28) from Harry J. Smith (hjsmithh(AT)sbcglobal.net), Oct 05 2009
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