This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A371055 #9 Mar 26 2024 01:59:23
%S A371055 102,1002,1022,1102,10002,10022,10222,11002,11022,11102,100002,100022,
%T A371055 100222,102222,110002,110022,110222,111002,111022,111102,1000002,
%U A371055 1000022,1000222,1002222,1022222,1100002,1100022,1100222,1102222,1110002,1110022,1110222
%N A371055 Ternary numbers consisting of a run of 1's, then a run of 0's, then a run of 2's.
%e A371055 10002 consists of a run 1, then a run 000, then a run 2.
%t A371055 Map[#[[1]] &, Select[Map[{#, Map[#[[1]] &, Split[IntegerDigits[#, 3]]] == {1, 0, 2}} &, Range[2, 4000, 3]], #[[2]] &]] (* A370543 *)
%t A371055 ToExpression[Map[IntegerString[#, 3] &, %]] (* this sequence *)
%t A371055 (* _Peter J. C. Moses_, Mar 06 2024 *)
%o A371055 (Python)
%o A371055 from itertools import count, islice
%o A371055 def A371055_gen(): # generator of terms
%o A371055 return (10**(l-a)*((10**a-1)//9)+((10**b-1)//9<<1) for l in count(3) for a in range(1,l-1) for b in range(1,l-a))
%o A371055 A371055_list = list(islice(A371055_gen(),20)) # _Chai Wah Wu_, Mar 25 2024
%Y A371055 Cf. A007089, A371054
%K A371055 nonn,base
%O A371055 1,1
%A A371055 _Clark Kimberling_, Mar 22 2024