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 A121109 #8 Aug 16 2015 08:56:28 %S A121109 26888999,4478976,338688,27648,2688,768,336,54,20,0 %N A121109 Trajectory of 26888999 under "x -> product of digits of x" map. %C A121109 This is the smallest number of persistence 9 (cf. A003001). %H A121109 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 A121109 NestList[Times@@IntegerDigits[#]&,26888999,9] (* _Harvey P. Dale_, Aug 16 2015 *) %Y A121109 Cf. A003001. %K A121109 nonn,fini,full,base %O A121109 1,1 %A A121109 _N. J. A. Sloane_, Aug 12 2006 %E A121109 Edited by _Charles R Greathouse IV_, Aug 06 2010