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 A046426 #10 Oct 15 2019 12:06:30 %S A046426 45,64,153,156,169,186,190,195,258,304,325,381,396,464,493,561,575, %T A046426 602,646,652,662,713,725,825,843,879,880,899,944,948,951,957,988,989, %U A046426 1007,1048,1106,1121,1166,1239,1252,1265,1267,1293,1390,1422,1474,1480,1486 %N A046426 Numbers requiring 6 steps to reach a prime under the prime factor concatenation procedure. %H A046426 Patrick De Geest, <a href="http://www.worldofnumbers.com/topic1.htm">Home Primes</a> %Y A046426 Cf. A037271, A046411. %K A046426 nonn,base %O A046426 1,1 %A A046426 _Patrick De Geest_, Jun 15 1998 %E A046426 Edited by _Charles R Greathouse IV_, Apr 28 2010