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 A199994 #10 Mar 30 2012 19:00:28 %S A199994 77,177,268,286,348,355,377,378,384,387,438,446,464,476,477,483,489, %T A199994 498,535,553,575,628,644,668,674,678,682,686,687,699,717,737,738,746, %U A199994 747,755,764,767,768,771,772,774,776,777,778,783,786,788,793,826,834,837 %N A199994 Composite numbers whose multiplicative persistence is 4. %C A199994 Complement of A046504 with respect to A046513. %e A199994 77 -> [ 49 ][ 36 ][ 18 ][ 8 ] -> one digit in four steps. %t A199994 persistence[n_] := Module[{cnt = 0, k = n}, While[k > 9, cnt++; k = Times @@ IntegerDigits[k]]; cnt]; Select[Range[1000], ! PrimeQ[#] && persistence[#] == 4 &] %Y A199994 Cf. A046504 (primes whose multiplicative persistence is 4). %K A199994 nonn,base %O A199994 1,1 %A A199994 _Jaroslav Krizek_, Nov 13 2011