A371111 - OEIS

%I #8 Apr 04 2024 10:29:52

%S 210,2100,2110,2210,21000,21100,21110,22100,22110,22210,210000,210210,

%T 211000,211100,211110,221000,221100,221110,222100,222110,222210,

%U 2100000,2100210,2102100,2102110,2102210,2110000,2110210,2111000,2111100,2111110,2210000

%N Ternary numbers that are concatenated runs C(1)A(1)B(1)C(2)A(2)B(2)...C(k)A(k)B(k), where A(i) is a run of 1's, B(i) a run of 0's, and C(i) a run of 2's, for i = 1..k.

%t Map[#[[1]] &, Select[Map[{#, DeleteDuplicates[Partition[Map[#[[1]] &, Split[IntegerDigits[#, 3]]], UpTo[3]]] == {{2, 1, 0}}} &,

%t Range[3, 3600, 3]], #[[2]] &]] (* this sequence *)

%t m = Map[{#, IntegerString[#, 3]} &, %];

%t Map[Last, ToExpression[m]] (* A371112 *)

%t (* _Peter J. C. Moses_, Mar 06 2024 *)

%Y Cf. A007088, A371105, A371106, A371107, A371108, A371109, A371110, A371112.

%K nonn,base

%O 1,1

%A _Clark Kimberling_, Mar 31 2024