A067496 Duplicate of A054565.
1, 18, 20, 22, 41, 43, 62, 64, 66, 83, 85, 87, 106, 108, 110, 127, 129, 131, 150, 152, 171, 173, 175, 194, 196, 215, 217, 219, 236, 238, 240
Offset: 1
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.
[3^n: n in [1..100] | Intseq(3^n)[#Intseq(3^n)] eq 3]; // Vincenzo Librandi, Oct 22 2018
Select[3^Range[70], First[IntegerDigits[#]]==3 &] (* Vincenzo Librandi, Oct 22 2018 *)
lista(nn) = {for (n=0, nn, if (digits(x=3^n)[1] == 3, print1(x, ", ")););} \\ Michel Marcus, Oct 22 2018