login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A321023 Numbers k such that sigma(k) = sigma(k + 15). 1
26, 62, 20840574, 25741470, 60765690, 102435795, 277471467, 361466454, 464465910, 1110512403, 1927430490, 2741174163, 3631266639, 3844534602, 3982743750, 4565968407, 4612184562, 4829319495, 4981969978, 7066794735, 13484870399, 14268004443, 14550390855, 15051147111 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..116 (terms < 2.5*10^12)
EXAMPLE
sigma(26) = sigma(41) = 42, sigma(62) = sigma(77) = 96.
PROG
(PARI) my(V=vector(15)); for(n=1, 2^28, my(s=sigma(n), r=(n%15)+1); if (s==V[r], print1(n-15, ", ")); V[r]=s)
CROSSREFS
Sequence in context: A039413 A043236 A044016 * A064867 A228512 A250605
KEYWORD
nonn
AUTHOR
Tomohiro Yamada, Oct 26 2018
EXTENSIONS
a(7)-a(9) from Amiram Eldar, Oct 26 2018
a(10)-a(24) from Giovanni Resta, Oct 26 2018
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 24 23:28 EDT 2024. Contains 373691 sequences. (Running on oeis4.)