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 A025144 #14 Jan 09 2024 16:10:23 %S A025144 18,19,20,24,25,26,28,30,33,34,35,37,39,42,45,51,53,54,56,57,59,60,63, %T A025144 71,72,73,74,75,77,78,80,83,90,98,99,100,101,102,108,110,117,120,289, %U A025144 305,308,382,383,385,386,387,388,389,390,391,392,394,395,398,405,406,407,408,409,410 %N A025144 Numbers k such that (#1's in s(1),...,s(k)) = (#1's in r(1),...,r(k)), where s = A025142 and r = A025143. %H A025144 Heiko Harborth editor, <a href="https://doi.org/10.1007/s005910050025">Probleme und Lösungen</a>, Mathematische Semesterberichte 44, pp. 93-96 (1997). See p. 94. %K A025144 nonn %O A025144 1,1 %A A025144 _Clark Kimberling_