OFFSET
1,1
COMMENTS
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..2000
EXAMPLE
100122 is an element because it contains two each of "0" and "1" and "2".
MATHEMATICA
Select[FromDigits/@Flatten[Permutations/@Table[PadRight[{}, 3n, {0, 1, 2}], {n, 2}], 1], Mod[IntegerLength[#], 3]==0&]//Sort (* Harvey P. Dale, Mar 15 2020 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Jonathan Vos Post, Apr 04 2012
EXTENSIONS
More terms from Alois P. Heinz, Apr 05 2012
STATUS
approved