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 A130431 #7 May 24 2023 17:19:40 %S A130431 0,10000000000,20000000000,30000000000,40000000000,50000000000, %T A130431 60000000000,70000000000,80000000000 %N A130431 Complete list of all 9 numbers n such that n is equal to the number of 9's in the decimal digits of all numbers <= n. %H A130431 Tanya Khovanova and Gregory Marton, <a href="https://arxiv.org/abs/2305.10357">Archive Labeling Sequences</a>, arXiv:2305.10357 [math.HO], 2023. See p. 4. %e A130431 a(5)=40000000000 because the number of 9's in the decimal digits of the numbers from 0 to 40000000000 is 40000000000 and this is the 5th such number. %Y A130431 Cf. A014778 for proof these sequences are finite; Also A101639, A101640, A101641, A130427, A130428, A130429, A130430; Cf. A130432 for the number of numbers in these sequences. %K A130431 base,fini,nonn,full %O A130431 1,2 %A A130431 _Graeme McRae_, May 26 2007