OFFSET
1,2
MATHEMATICA
a[n_] := DivisorSum[n, # &, Divisible[n, EulerPhi[#]] &]; Array[a, 100]
PROG
(PARI) a(n) = sumdiv(n, d, if (!(n % eulerphi(d)), d)); \\ Michel Marcus, Apr 28 2023
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wesley Ivan Hurt, Apr 28 2023
STATUS
approved