OFFSET
1,2
COMMENTS
It seems that odd k's {1, 3, 21, 243, 1323, 3087, ...} are relatively rare. A235353 is a subsequence of this sequence.
This sequence is infinite since A058891 is a subsequence. - Amiram Eldar, Feb 26 2023
EXAMPLE
MATHEMATICA
Select[Range[10^4], IntegerQ[#/DivisorSigma[0, #] + #/EulerPhi[#]] &] (* Amiram Eldar, Feb 26 2023 *)
PROG
(Python)
from math import prod
from itertools import count, islice
from sympy import factorint
def A360940_gen(startvalue=1): # generator of terms >= startvalue
for k in count(max(startvalue, 1)):
f = factorint(k)
t = prod(p**(e-1)*(p-1) for p, e in f.items())
s = prod(e+1 for e in f.values())
if not k*(s+t)%(s*t):
yield k
CROSSREFS
KEYWORD
nonn
AUTHOR
Ctibor O. Zizka, Feb 26 2023
STATUS
approved