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 A023699 #13 Jul 26 2023 13:54:12 %S A023699 2,5,6,7,11,14,15,16,18,19,21,22,29,32,33,34,38,41,42,43,45,46,48,49, %T A023699 54,55,57,58,63,64,66,67,83,86,87,88,92,95,96,97,99,100,102,103,110, %U A023699 113,114,115,119,122,123,124,126,127,129,130,135,136,138,139,144,145 %N A023699 Numbers with a single 2 in their ternary expansion. %H A023699 Amiram Eldar, <a href="/A023699/b023699.txt">Table of n, a(n) for n = 1..10000</a> %t A023699 Select[ Range[ 162 ], (Count[ IntegerDigits[ #, 3 ], 2 ]==1)& ] %t A023699 Select[Range[200],DigitCount[#,3,2]==1&] (* _Harvey P. Dale_, Jul 26 2023 *) %Y A023699 Cf. A007089, A023693, A291907. %K A023699 nonn,base,easy %O A023699 1,1 %A A023699 _Olivier Gérard_