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 A121105 #8 Sep 13 2024 17:58:02 %S A121105 679,378,168,48,32,6 %N A121105 Trajectory of 679 under "x -> product of digits of x" map. %C A121105 This is the smallest number of persistence 5 (cf. A003001). %H A121105 N. J. A. Sloane, <a href="http://neilsloane.com/doc/persistence.html">The persistence of a number</a>, J. Recreational Math., 6 (1973), 97-98. %t A121105 Most[FixedPointList[Times@@IntegerDigits[#]&,679,7]] (* _Harvey P. Dale_, Sep 13 2024 *) %Y A121105 Cf. A003001. %K A121105 nonn,fini,full,base %O A121105 1,1 %A A121105 _N. J. A. Sloane_, Aug 12 2006 %E A121105 Edited by _Charles R Greathouse IV_, Aug 05 2010