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 A046427 #11 Oct 15 2019 12:07:22
%S A046427 91,128,196,305,344,416,438,456,554,656,690,707,746,750,779,897,910,
%T A046427 950,1014,1060,1098,1122,1199,1209,1247,1380,1507,1545,1606,1679,1680,
%U A046427 1700,1711,1769,1833,1884,1887,1888,1928,1971,1984,2000,2169,2176,2192,2198
%N A046427 Numbers requiring 7 steps to reach a prime under the prime factor concatenation procedure.
%H A046427 Patrick De Geest, <a href="http://www.worldofnumbers.com/topic1.htm">Home Primes</a>
%t A046427 numberSteps[x_]:=Module[{n,steps,digits,i},n=x; steps=0; While[ !PrimeQ[n]&&steps<10,factors=FactorInteger[n]; digits={}; For[i=1,i<=Length[factors],i++, digits=Join[digits, Flatten[ Table[IntegerDigits[factors[[i,1]]],{factors[[i,2]]}]]];]; n=FromDigits[digits]; steps++;]; Return[steps]]; For[i=1,i<2000,i++,If[numberSteps[i]==7,Print[i];];]; (* Sam Handler (sam_5_5_5_0(AT)yahoo.com), Aug 16 2006 *)
%Y A046427 Cf. A037271, A046411.
%K A046427 nonn,base
%O A046427 1,1
%A A046427 _Patrick De Geest_, Jun 15 1998
%E A046427 More terms from Sam Handler (sam_5_5_5_0(AT)yahoo.com), Aug 16 2006
%E A046427 Extended and edited by _Charles R Greathouse IV_, Apr 28 2010