OFFSET
1,2
COMMENTS
Since A001615(k) > k for k > 1, a(n) < 2*n.
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(3) = 4 because A001615(4) = 6.
MAPLE
psi:= proc(n) local p;
n * mul(1+1/p, p = numtheory:-factorset(n))
end proc:
N:= 100: # for a(1) to a(N)
V:= Vector(N, -1):
for k from 3 to 2*N-1 do
v:= psi(k)/2;
if v <= N and V[v] = -1 then V[v]:= k fi
od:
convert(V, list);
CROSSREFS
KEYWORD
sign,look
AUTHOR
Robert Israel, Sep 15 2024
STATUS
approved