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 A039412 #11 Jun 30 2021 03:58:08 %S A039412 25,52,125,152,205,215,235,245,250,251,253,254,256,257,258,259,265, %T A039412 275,285,295,325,352,425,452,502,512,520,521,523,524,526,527,528,529, %U A039412 532,542,562,572,582,592,625,652,725,752,825,852,925,952,1025,1052 %N A039412 Numbers whose base-10 representation has the same nonzero number of 2's and 5's. %K A039412 nonn,base,easy %O A039412 1,1 %A A039412 _Olivier Gérard_