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 A046259 #9 Jul 14 2015 01:38:50
%S A046259 9,11,21,21,23,33,37,93,119,129,133,147,293,321,429,433,497,627,661,
%T A046259 897,1161,1187,1197,1711,1769,1807,2097,2099,4143,4149,4197,4587,4587,
%U A046259 5629,5711,5889,6153,6351,6399,6511,6651,7179,7563,7661,8071,8163,9663
%N A046259 a(1) = 9; a(n) is smallest number >= a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.
%t A046259 a[1] = 9; a[n_] := a[n] = Block[{k = a[n - 1], c = IntegerDigits @ Table[ a[i], {i, n - 1}]}, While[ !PrimeQ[ FromDigits @ Flatten @ Append[c, IntegerDigits[k]]], k += 2]; k]; Table[ a[n], {n, 48}] (* _Robert G. Wilson v_, Aug 05 2005 *)
%Y A046259 Cf. A069611, A074345, A033680, A033679, A033681, A046254, A046255, A046256, A046257, A046258, A111524.
%K A046259 nonn
%O A046259 1,1
%A A046259 _Patrick De Geest_, May 15 1998