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A063797
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Numbers n such that sigma(d(n^3))==d(sigma(n^2)), where d(n) is the number of divisors of n.
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0
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1, 961, 1369, 2209, 2809, 3721, 7921, 9409, 11881, 12769, 17161, 18769, 22201, 24649, 27889, 32761, 38809, 44521, 58081, 73441, 80089, 94249, 96721, 100489, 109561, 121801
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OFFSET
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1,2
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COMMENTS
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Not all a(n) are 1 mod 24. First counterexample is 5036684. But for a prime p, with sigma(p^2) squarefree and omega(sigma(p^2)==3, p^2 is in a(n). It also appears that for these primes p^2 = 1 mod 24. - Lambert Herrgesell (lambert.herrgesell(AT)googlemail.com), Jan 08 2007
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LINKS
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Table of n, a(n) for n=1..26.
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PROG
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(PARI) for(n=1, 10^7, if(sigma(numdiv(n^3))==numdiv(sigma(n^2)), print(n)))
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CROSSREFS
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Sequence in context: A157851 A147883 A166964 * A098207 A158414 A031740
Adjacent sequences: A063794 A063795 A063796 * A063798 A063799 A063800
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KEYWORD
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nonn
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AUTHOR
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Jason Earls (zevi_35711(AT)yahoo.com), Aug 19 2001
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STATUS
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approved
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