OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..850
EXAMPLE
We have sigma(48)=sigma(75)=124, and gcd(48, 75) = 3, hence 124 is in the sequence.
Likewise, we have sigma(x)=2912 for x=[1116, 1236, 1701, 2007, 2181], with gcd 3.
MAPLE
N:= 10^5: # for terms <= N
V:= Vector(N):
for x from 1 to N do
s:= numtheory:-sigma(x);
if s <= N then
if V[s] = 0 then V[s]:= x
else V[s]:= igcd(V[s], x)
fi
fi
od: select(t -> V[t]=3, [$1..N]); # Robert Israel, Aug 18 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Marcus, Apr 26 2014
STATUS
approved