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 A046515 #14 Feb 16 2025 08:32:39 %S A046515 6788,6878,6887,7688,7868,7886,8678,8687,8768,8786,8867,8876,16788, %T A046515 16878,16887,17688,17868,17886,18678,18687,18768,18786,18867,18876, %U A046515 23788,23878,23887,24678,24687,24768,24786,24867,24876,26478,26487 %N A046515 Numbers with multiplicative persistence value 6. %H A046515 Robert Israel, <a href="/A046515/b046515.txt">Table of n, a(n) for n = 1..10000</a> %H A046515 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/MultiplicativePersistence.html">Multiplicative Persistence</a> %e A046515 6788 -> [ 2688 ][ 768 ][ 336 ][ 54 ][ 20 ][ 0 ] -> one digit in six steps. %p A046515 mp:= proc(n) option remember; %p A046515 if n <= 9 then return 0 fi; %p A046515 1+procname(convert(convert(n,base,10),`*`)) %p A046515 end proc: %p A046515 select(mp=6, [$1..30000]); # _Robert Israel_, Feb 12 2019 %Y A046515 Cf. A003001, A014120, A046506. %K A046515 nonn,base %O A046515 1,1 %A A046515 _Patrick De Geest_, Sep 15 1998 %E A046515 Offset corrected by _Robert Israel_, Feb 12 2019