OFFSET
1,2
COMMENTS
See A228870 for the numbers not in this sequence.
Also, positive integers n such that (p-1) does not divide n for every odd prime p dividing n (cf. A124240). - Max Alekseyev, Sep 07 2013
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
MATHEMATICA
Select[Range[100], Mod[2*Sum[PowerMod[k, #, #], {k, #}], #] == 0 &]
CROSSREFS
KEYWORD
nonn
AUTHOR
T. D. Noe, Sep 06 2013
STATUS
approved