OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
MATHEMATICA
ds[n_] := Plus @@ IntegerDigits[n]; f[n_] := ds[n] + Total[ds /@ FactorInteger[n][[;; , 1]]]; s = {}; f1 = 1; Do[f2 = f[n]; If[f1 == f2, AppendTo[s, n-1]]; f1 = f2, {n, 2, 1000}]; s (* Amiram Eldar, Nov 24 2019 *)
SequencePosition[Flatten[Table[Total[IntegerDigits[n]]+Total[Flatten[IntegerDigits/@FactorInteger[n][[All, 1]]]], {n, 1000}]], {x_, x_}][[All, 1]](* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jan 09 2021 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
STATUS
approved