OFFSET
1,3
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..1001
FORMULA
a(n) = Sum_{d|n} 2^(d-1) * A349453(n/d).
MATHEMATICA
s[1] = 1; s[n_] := s[n] = -DivisorSum[n, s[#] * 3^(n/# - 1) &, # < n &]; a[n_] := DivisorSum[n, 2^(# - 1) * s[n/#] &]; Array[a, 30] (* Amiram Eldar, Nov 22 2021 *)
PROG
CROSSREFS
KEYWORD
sign
AUTHOR
Antti Karttunen, Nov 22 2021
STATUS
approved