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 A050674 #23 Oct 15 2019 12:02:28
%S A050674 11,13,17,19,37,41,49,53,59,61,67,71,79,89,97,107,109,113,131,133,151,
%T A050674 161,167,179,193,199,211,217,221,247,257,259,277,287,289,293,313,319,
%U A050674 323,337,343,359,373,377,383,389,409,457,469,479,481,493,511,527,553
%N A050674 Inserting a digit '0' between adjacent digits of n makes a prime.
%e A050674 373 becomes 3(0)7(0)3 which is prime 30703.
%t A050674 (* This program works in Mathematica 6.0 and later *)
%t A050674 Select[Range[11, 1000,2], PrimeQ[FromDigits[Riffle[IntegerDigits[#], 0]]] &] (* _T. D. Noe_, Dec 22 2010 *)
%t A050674 (* The following program has been tested in Mathematica 5.1 and it works *)
%t A050674 Reap[c = 0; d = 0; Do[If[MemberQ[{1, 3, 7, 9}, Mod[n, 10]], id = IntegerDigits[n]; Do[id[[k]] = {id[[k]], d}, {k, Length[id] - 1}]; If[PrimeQ[FromDigits[Flatten[id]]], Sow[n]; c++; If[c > 999, Break[]]]], {n, 11, 20000}]][[2,1]] (* _Zak Seidov_, Dec 22 2010 *)
%Y A050674 Cf. A050711, A050712, A050713, A050715, A050716, A050717, A050718, A050719.
%K A050674 nonn,base
%O A050674 1,1
%A A050674 _Patrick De Geest_, Aug 15 1999
%E A050674 Offset set to 1 by _Georg Fischer_, Oct 15 2019