OFFSET
1,1
MATHEMATICA
f[n_] := Length[StringPosition[ToString[FromDigits[IntegerDigits[n, 6]]], "33", 1]]; Select[Table[n, {n, 10000}], f[#] > 0 && f[# - 1] == 0 &] (* Vladimir Joseph Stephan Orlovsky, Jul 20 2011 *)
SequencePosition[Table[If[SequenceCount[IntegerDigits[n, 6], {3, 3}]>0, 1, 0], {n, 2000}], {0, 1}][[All, 2]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 14 2017 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
STATUS
approved