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Search: id:A125249
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| A125249 |
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Numbers n for which the absolute values of the abundances of n, n^2 and n^3 are all prime numbers. |
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+0
1
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| 289, 201601, 222784, 638401, 868562, 910116, 4694048, 4950625, 8994001, 9054081, 19855936, 30085225, 32385152, 47623801, 55100929, 72182016, 78952178, 85099058, 86303522, 91910569
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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n=289; The abundance of 289 is -271, the abundance of 83521 (289^2) is -78301, the abundance of 24137569 (289^3) is -22628971 - all of which are negatives of primes.
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PROGRAM
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(PARI) {for(n=1, 1000000, if(isprime(abs(sigma(n)-2*n))&&isprime(abs(sigma(n^2)-2*n^2))&&isprime(abs(sigma(n^3)-2*n^3)), print1(n, ", ")))}
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CROSSREFS
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Cf. A088005, A125236, A125237.
Sequence in context: A008367 A112077 A114762 this_sequence A013761 A013883 A091680
Adjacent sequences: A125246 A125247 A125248 this_sequence A125250 A125251 A125252
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KEYWORD
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nonn
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AUTHOR
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Jason G. Wurtzel (j_seq(AT)wurtzel.com), Nov 26 2006
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EXTENSIONS
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More terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), May 29 2007
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