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 A089702 #6 Aug 13 2017 21:43:44 %S A089702 2,3,3,3,3,23,43,59,67,83,199,239,421,569,613,1307,2017,2129,2467, %T A089702 2741,2953,3011,3319,3413,3607,3617,5449,6917,7333,7529,8389,10211, %U A089702 10357,12641,12703,15077,17107,21341,21799,22469,32911,33587,33613,33647 %N A089702 a(1) = 2 then primes in nondecreasing order such that every concatenation is prime. %e A089702 2,23,233,2333,23333,2333323 etc. are primes. %p A089702 ds:=proc(s) local j: RETURN(add(s[j]*10^(j-1),j=1..nops(s))):end: a:=[2]: k:=1: for n from 1 to 50 do l:=nops(a): for i from k do p:=ithprime(i): if isprime(ds([op(convert(p,base,10)),seq(op(convert(a[l-j],base,10)),j=0..l-1)])) then a:=[op(a),p]: k:=i: break fi od od: op(a); # C. Ronaldo %Y A089702 Cf. A089703. %K A089702 base,nonn %O A089702 0,1 %A A089702 _Amarnath Murthy_, Nov 10 2003 %E A089702 More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Dec 25 2004