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 A046422 #9 Aug 11 2024 14:41:31 %S A046422 4,9,24,30,32,36,38,42,50,55,57,60,68,74,75,88,92,94,99,102,106,108, %T A046422 110,122,134,140,155,158,174,194,206,209,215,231,244,254,272,280,287, %U A046422 298,299,306,314,323,332,334,346,351,362,365,371,374,398,413,415,417 %N A046422 Numbers requiring 2 steps to reach a prime under the prime factor concatenation procedure. %H A046422 P. De Geest, <a href="https://www.worldofnumbers.com/topic1.htm">Home Primes</a> %e A046422 24 = 2*2*2*3, 2223 = 3*3*13*19, 331319 is prime. %Y A046422 Cf. A037271, A046411. %K A046422 nonn,base %O A046422 1,1 %A A046422 _Patrick De Geest_, Jun 15 1998 %E A046422 Edited by _Charles R Greathouse IV_, Apr 28 2010