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 A043421 #11 Apr 24 2021 17:33:23 %S A043421 8,16,24,32,40,48,56,65,66,67,68,69,70,71,72,80,88,96,104,112,120,129, %T A043421 130,131,132,133,134,135,136,144,152,160,168,176,184,193,194,195,196, %U A043421 197,198,199,200,208,216,224,232,240,248,257 %N A043421 Numbers having one 0 in base 8. %t A043421 Select[Range[300],DigitCount[#,8,0]==1&] (* _Harvey P. Dale_, Jul 15 2014 *) %Y A043421 Cf. A007094. %K A043421 nonn,base %O A043421 1,1 %A A043421 _Clark Kimberling_