OFFSET
1,2
LINKS
Michael De Vlieger, Table of n, a(n) for n = 1..6811 (all in a(n) for n = 1..2^28)
MATHEMATICA
nn = 5000; c[_] = False; f[n_] := DivisorSigma[0, n]; a[1] = m = 1; r = 0; Reap[Do[(If[c[#], a[n] = # + f[a[m]] ; m++, a[n] = f[#]]; c[#] = True; If[# > r, r = #; Sow[n - 1]]) &[a[n - 1]], {n, 2, nn}] ][[-1, -1]] (* Michael De Vlieger, Apr 08 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Apr 08 2023
STATUS
approved