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 A046425 #9 Oct 15 2019 12:06:01 %S A046425 14,34,147,164,183,214,216,230,236,248,252,276,285,309,324,335,404, %T A046425 405,444,482,484,486,508,520,527,540,550,570,580,633,636,638,658,689, %U A046425 704,730,738,802,814,852,915,935,954,959,960,981,996,1004,1037,1046,1058 %N A046425 Numbers requiring 5 steps to reach a prime under the prime factor concatenation procedure. %H A046425 Patrick De Geest, <a href="http://www.worldofnumbers.com/topic1.htm">Home Primes</a> %e A046425 14 = 2*7 -> 27 = 3*3*3 -> 333 = 3*3*37 -> 3337 = 47*71 -> 4771 = 13*367 and 13367 is prime. %Y A046425 Cf. A037271, A046411. %K A046425 nonn,base %O A046425 0,1 %A A046425 _Patrick De Geest_, Jun 15 1998