A370920 - OEIS

%I #7 Mar 17 2024 23:37:36

%S 6,15,18,19,33,42,45,46,54,55,57,58,60,87,96,99,100,114,123,126,127,

%T 135,136,138,139,141,162,163,165,166,168,171,172,174,175,177,180,181,

%U 249,258,261,262,276,285,288,289,297,298,300,301,303,330,339,342,343

%N Positive integers in whose ternary representation 2 occurs at least once, and every 2 is followed by 0.

%F The ternary representations of 6, 15, and 18 are 20, 120, and 200.

%t Map[#[[1]] &, Select[Map[{#, #[[1]] > 0 && #[[1]] == #[[2]] &[{Length[

%t StringCases[#, "2"]], Length[StringCases[#, "20"]]}] &[

%t IntegerString[#, 3]]} &, Range[500]], #[[2]] &]]   (* _Peter J. C. Moses_, Mar 05 2024 *)

%Y Cf. A007089, A074940.

%Y Cf. A370916, A370917, A370918, A370919, A370921, A370922, A370923.

%K nonn,base

%O 1,1

%A _Clark Kimberling_, Mar 16 2024