The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A293992 Numbers n such that sigma(n)-n-1 is a perfect number. 0
 8, 115, 187, 1375, 2455, 8143, 13543, 18261, 21103, 23479, 40615, 41623, 43279, 49183, 49441, 51703, 56743, 61063, 61279, 61423, 89287, 95551, 137887, 214303, 331567, 379807, 476071, 715471, 1422871, 1515967, 1793527, 1977127, 2431087, 3098527, 3663871 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS FORMULA Numbers n such that sigma(n)-n-1 is a perfect number. EXAMPLE For n=8 it is sigma(8)-8-1=6; for n=115 it is sigma(115)-115-1=28 MATHEMATICA With[{pn=PerfectNumber[Range[10]]}, Select[Range[37*10^5], MemberQ[pn, DivisorSigma[ 1, #]-#-1]&]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Feb 04 2019 *) CROSSREFS Sequence in context: A220635 A113670 A156468 * A220575 A240890 A241105 Adjacent sequences:  A293989 A293990 A293991 * A293993 A293994 A293995 KEYWORD nonn AUTHOR Zdenek Cervenka, Oct 21 2017 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 16 14:16 EDT 2021. Contains 345057 sequences. (Running on oeis4.)