OFFSET
1,1
COMMENTS
n such that n-2 is the least k such that n divides A062727(k) = sigma(k^k).
Are all terms prime?
EXAMPLE
17 is in the sequence because 17 divides sigma(15^15) = 821051025385244160 but does not divide sigma(k^k) for any k < 15.
MAPLE
N:= 20000:
S:= {$1..N}: # to get terms <= N
for kk from 1 while S <> {} do
v:= numtheory:-sigma(kk^kk);
F:= select(t -> v mod t = 0, S);
for nn in F do
B[nn]:= kk
od;
S:= S minus F;
od:
select(t -> B[t]=t-2, [$1..N]);
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert Israel, Aug 09 2016
STATUS
approved