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 A199999 #10 Feb 16 2025 08:33:16 %S A199999 26888999,26889899,26889989,26889998,26898899,26898989,26898998, %T A199999 26899898,26899988,26988899,26988989,26988998,26989889,26989898, %U A199999 26989988,26998889,26998898,26998988,26999888,28688999,28689899,28689989,28689998,28698989,28698998,28699898 %N A199999 Composite numbers whose multiplicative persistence is 9. %C A199999 Complement of A046509 with respect to A046518. %H A199999 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/MultiplicativePersistence.html">Multiplicative Persistence</a> %e A199999 26888999 -> [ 4478976 ][ 338688 ][ 27648 ][ 2688 ][ 768 ][ 336 ][ 54 ][ 20 ][ 0 ] -> one digit in nine steps. %Y A199999 Cf. A046509 (primes whose multiplicative persistence is 9). %K A199999 nonn,base %O A199999 1,1 %A A199999 _Jaroslav Krizek_, Nov 13 2011