_Yasutoshi Kohmoto (zbi74583(AT)boat.zero.ad.jp), _, May 10 2008

Definition rewritten by _M. F. Hasler, _, May 10 2008

editing

approved

Walter Nissen, <a href="http://upforthecount.com">Home Page</a> (listed in lieu of email address)

Cf. A159907 = (half-integer abundancy) [From _. - _Gerard P. Michon_, May 10 2009]

Corrected a(1), corrected and a(3) confirmed a(3) - _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.

a(10)=215594611071909888000 [and above] from _Michel Marcus, _, added by Gerard P. Michon, Jun 04 2009

approved

editing

editing

approved

200286975596707184640 belongs to this sequence. [From _- _Gerard P. Michon_, May 10 2009]

81703797123392614369698250752 is in this sequence. [From _- _Gerard P. Michon_, May 11 2009]

G. P. Michon, <a href="/A141645/b141645.txt">Table of n, a(n) for n = 1..27</a>

(PARI) is(n)=sigma(n, -1)==9/2 \\ Charles R Greathouse IV, Mar 09 2014

approved

editing

Corrected a(1), confirmed a(3) - _Ray Chandler (rayjchandler(AT)sbcglobal.net), _, Sep 18 2008

200286975596707184640 belongs to this sequence. [From _Gerard P. Michon (g.michon(AT)att.net), _, May 10 2009]

81703797123392614369698250752 is in this sequence. [From _Gerard P. Michon (g.michon(AT)att.net), _, May 11 2009]

G. P. Michon, <a href="http://www.numericana.com/answer/numbers.htm#multiperfect">Multiperfect and hemiperfect integers</a> [From _Gerard P. Michon (g.michon(AT)att.net), _, Jun 04 2009]

Cf. A159907 = (half-integer abundancy) [From _Gerard P. Michon (g.michon(AT)att.net), _, May 10 2009]

a(7) = 15338300494970880 added by _Gerard P. Michon (g.michon(AT)att.net), _, May 10 2009.

a(10)=215594611071909888000 [and above] from Michel Marcus, added by _Gerard P. Michon (g.michon(AT)att.net), _, Jun 04 2009

Is it certain that there are no other terms below the highest value shown? - _N. J. A. Sloane (njas(AT)research.att.com), _, Sep 07 2008

G. P. Michon, <a href="/A141645/b141645.txt">Table of n, a(n) for n=1..27</a>

nonn,new

nonn