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 A141645 Numbers n such that sigma(n)/n = 9/2. 11
 8910720, 17428320, 8583644160, 57629644800, 206166804480, 1416963251404800, 15338300494970880, 6275163455171297280, 200286975596707184640, 215594611071909888000, 5997579964837140234240, 39887491844324122951680 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS 200286975596707184640 belongs to this sequence. - Gerard P. Michon, May 10 2009 81703797123392614369698250752 is in this sequence. - Gerard P. Michon, May 11 2009 LINKS G. P. Michon, Table of n, a(n) for n = 1..27 G. P. Michon, Multiperfect and hemiperfect integers [From Gerard P. Michon, Jun 04 2009] Walter Nissen, Abundancy : Some Resources PROG (PARI) is(n)=sigma(n, -1)==9/2 \\ Charles R Greathouse IV, Mar 09 2014 CROSSREFS Cf. A055153, A141643, A159271, A160678. Cf. A159907 = (half-integer abundancy). - Gerard P. Michon, May 10 2009 Sequence in context: A078143 A216003 A293374 * A217655 A151933 A337964 Adjacent sequences:  A141642 A141643 A141644 * A141646 A141647 A141648 KEYWORD nonn AUTHOR Yasutoshi Kohmoto, May 10 2008 EXTENSIONS Definition rewritten by M. F. Hasler, May 10 2008 Is it certain that there are no other terms below the highest value shown? - N. J. A. Sloane, Sep 07 2008 a(1) corrected and a(3) confirmed by Ray Chandler, Sep 18 2008 Missing term a(2)=17428320 communicated by Walter Nissen, Apr 17 2009. There are no further terms through 2^34. Missing term a(4) inserted and a(6) and a(8) added by Grzegorz Lach (137.036(AT)gmail.com), Apr 18 2009. a(4) was also sent by Avinoam Kalma (a.kalma(AT)gmail.com), Apr 20 2009. a(7) = 15338300494970880 added by Gerard P. Michon, May 10 2009. a(10)=215594611071909888000 [and above] from Michel Marcus, added by Gerard P. Michon, Jun 04 2009 STATUS approved

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Last modified November 26 07:48 EST 2022. Contains 358353 sequences. (Running on oeis4.)