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 A224400 #18 Dec 09 2014 03:34:16
%S A224400 20,30,32,50,70,74,76,91,92,95,98,110,130,170,172,175,176,190,194,200,
%T A224400 203,209,217,230,232,272,275,290,292,296,300,301,302,310,319,320,322,
%U A224400 323,329,332,370,371,374,376,391,392,394,395,398,407,437,470,473,475
%N A224400 Composite numbers that become prime when their digits are put in nondecreasing order.
%C A224400 Conjecture: a(n) ~ 7.75*n.
%H A224400 Christian N. K. Anderson, <a href="/A224400/b224400.txt">Table of n, a(n) for n = 1..10000</a>
%e A224400 217 = 7*31, but 127 is prime. 302 = 2*151, but 23 is prime.
%t A224400 Select[Range[500], ! PrimeQ[#] && PrimeQ[FromDigits[Sort[IntegerDigits[#]]]] &] (* _T. D. Noe_, Apr 05 2013 *)
%o A224400 (R) j=1; y=c(); library(gmp)
%o A224400 while(length(y)<1000) {
%o A224400 if(isprime((j=j+1))==0) {
%o A224400 x=sort(as.numeric(strsplit(as.character(j),spl="")[[1]]))
%o A224400 if(isprime(paste(x[x>0],collapse=""))>0) y=c(y,j) #drop leading zeros
%o A224400 }
%o A224400 }
%Y A224400 Subset of A007935.
%Y A224400 Cf. A068653, A076055, A224402.
%K A224400 nonn,base
%O A224400 1,1
%A A224400 _Christian N. K. Anderson_ and _Kevin L. Schwartz_, Apr 05 2013