OFFSET
1,4
LINKS
MATHEMATICA
d[n_] := Module[{k = n, p = 2, s = 0, r}, While[{k, r} = QuotientRemainder[k, p]; k != 0 || r != 0, s += r; p = NextPrime[p]]; s]; a[n_] := DivisorSum[n, d[#] &, # < n &]; Array[a, 100] (* Amiram Eldar, Mar 05 2024 *)
PROG
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Antti Karttunen, Oct 02 2018
STATUS
approved