OFFSET
1,10
COMMENTS
Even period lengths from 2 to 16 arise for the first time from n equal to 11, 263, 149, 3244, 7339, 6929, 31201, and 47397, respectively. Are periods of odd length greater than 1 possible? - Giovanni Resta, Nov 27 2019
EXAMPLE
Some terms and corresponding sequences:
a(1)=1 1,1,1,(1),...
a(11)=1144 11,22,88,1408,18304,1144,11440,(1144,11440),...
a(14)=10 14,70,10,10,(10),...
a(263)=1374175 263,2893,63646,1591150,72325,(1374175,38476900,1423645300,50844475),...
MATHEMATICA
a[k_] := Block[{aa, w, t, p}, aa[1] = k; aa[n_] := aa[n] = Block[{s = Plus @@ IntegerDigits@ aa[n-1]}, aa[n-1] If[Mod[aa[n-1], s] == 0, 1/s, s]]; w = Array[aa, 50]; While[({t, p} = FindTransientRepeat[w, 2])[[2]] == {}, w = Array[aa, Length[w] + 50]]; Min[p]]; Array[a, 60]; (* Giovanni Resta, Nov 27 2019 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Amarnath Murthy, Aug 09 2005
EXTENSIONS
Edited and extended by Giovanni Resta, Nov 27 2019
STATUS
approved