OFFSET
1,1
COMMENTS
The composite terms in this sequence start 6, 9, 12, 21, 63, 121, 133, 172, 190, 196, ... - R. J. Mathar, Jan 14 2011
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
FORMULA
A180060(a(n)) = 4.
MATHEMATICA
Select[Range[300], PowerMod[2, PowerMod[2, #, #], #]==4&] (* Harvey P. Dale, Sep 08 2016 *)
PROG
(PARI) s=[]; for(n=1, 1000, if((2^(2^n%n)%n)==4, s=concat(s, n))); s \\ Colin Barker, Jun 27 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Jan 14 2011
EXTENSIONS
Terms corrected by R. J. Mathar, Jan 14 2011
STATUS
approved