OFFSET
1,1
COMMENTS
a(7) > 6*10*8.
LINKS
Thomas Fink, Recursively divisible numbers, arXiv:1912.07979 [math.NT], 2019.
MATHEMATICA
s[1] = 1; s[n_] := s[n] = n + DivisorSum[n, s[#] &, # < n &]; seq = {}; s1 = s[1]; Do[s2 = s[n]; If[s1 == s2, AppendTo[seq, n-1]]; s1 = s2, {n, 2, 10^5}]; seq
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Amiram Eldar, Apr 11 2020
STATUS
approved