[seqfan] Skolem with digits

[Eric Angelini]

Hello SeqFans,
This is a Skolem-like sequence S where all natural integer appear exactly twice and where two equal terms T of S are separated by exactly T < digits >.

S=1,2,1,3,2,4,5,3,6,7,4,8,5,12,6,9,7,11,8,10,aaa,9,12,13,11,10,14,16,18,bbb,
13,15,ccc,14,17,16,19,18,20,15,21,23,ddd,17,22,24,19,eee,20,fff,21,25,23, 
26,28,22,27,24,29,31,33,35,37,...

The above 3-digit terms aaa, bbb, ccc,... are missing (I am unable
to compute them by hand). Could someone find them and extend S?
S should be, of course, the lexicofirst such sequence.
S could be seen as the "digit-version" of http://oeis.org/A026272

Best,
É.