OFFSET
1,1
COMMENTS
For the first 26 terms, the quotient (sigma(n)/phi(n)) is 2 or 3.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..6654 (terms below 6.5*10^14, calculated using data from Jud McCranie)
MAPLE
with(numtheory); BNM11:=[]: for z from 1 to 1 do for n from 1 to 500000 do m:=12*n+11; if sigma(m) mod phi(m) = 0 then BNM11:=[op(BNM11), m] fi; od; od; BNM11;
MATHEMATICA
Select[Range[10^7], Mod[#, 12] == 11 && Divisible[DivisorSigma[1, #], EulerPhi[#]] &] (* Amiram Eldar, Dec 04 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Walter Kehowski, Sep 13 2005
EXTENSIONS
a(6)-a(26) from Donovan Johnson, Aug 30 2012
STATUS
approved