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 A043393 #15 Apr 23 2023 21:58:02 %S A043393 7,14,21,28,35,42,50,51,52,53,54,55,56,63,70,77,84,91,99,100,101,102, %T A043393 103,104,105,112,119,126,133,140,148,149,150,151,152,153,154,161,168, %U A043393 175,182,189,197,198,199,200,201,202,203,210 %N A043393 Numbers whose base-7 representation contains exactly one 0. %t A043393 Select[Range[250],DigitCount[#,7,0]==1&] (* _Harvey P. Dale_, Sep 26 2019 *) %Y A043393 Cf. A007093. %K A043393 nonn,base %O A043393 1,1 %A A043393 _Clark Kimberling_