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 A141643 Numbers n such that sigma(n)/n = 5/2. 9
 24, 91963648, 10200236032 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS There are no other terms through 2^34. - Walter Nissen, Apr 17 2009 No more terms below 10^12. - Jud McCranie, Aug 30 2013 LINKS Table of n, a(n) for n=1..3. G. P. Michon, Multiperfect and hemiperfect numbers Walter Nissen, Abundancy : Some Resources Walter Nissen, Abundancy : Some Resources Walter Nissen, Primitive Friendly Pairs with friends < 2^34 with denom < 20000 MATHEMATICA Select[Range[100000], DivisorSigma[1, #]/# == 5/2 &] (* Robert Price, Apr 03 2019 *) PROG (PARI) isok(n) = sigma(n, -1) == 5/2; \\ Michel Marcus, Apr 04 2019 CROSSREFS Cf. A055153, A141645, A159271, A160678. Sequence in context: A255322 A319900 A172803 * A275026 A297424 A013910 Adjacent sequences: A141640 A141641 A141642 * A141644 A141645 A141646 KEYWORD nonn,more,bref AUTHOR Yasutoshi Kohmoto, May 10 2008 EXTENSIONS Definition rewritten by M. F. Hasler, May 10 2008 First three terms confirmed by Ray Chandler, Sep 18 2008 STATUS approved

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Last modified September 28 22:22 EDT 2023. Contains 365739 sequences. (Running on oeis4.)