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 A216307 #13 Apr 23 2019 18:28:17
%S A216307 2,5,8,17,23,26,35,37,38,44,50,56,59,65,73,101,110,112,122,128,143,
%T A216307 149,154,155,161,175,197,206,233,239,254,269,290,296,308,320,331,332,
%U A216307 353,373,392,401,407,413,425,428,464,467,479,490,499,500,511,527,530
%N A216307 Values of k such that 10*k+3 and 10*k+9 alone are prime between 10*k and 10*k+9.
%H A216307 V. Raman, <a href="/A216307/b216307.txt">Table of n, a(n) for n = 1..10000</a>
%F A216307 a(n) >> n log^2 n. - _Charles R Greathouse IV_, Sep 07 2012
%t A216307 t = {}; Do[ps = Select[Range[10*n, 10*n + 9], PrimeQ]; If[ps == {10*n + 3, 10*n + 9}, AppendTo[t, n]], {n, 0, 782}]; t (* _T. D. Noe_, Sep 04 2012 *)
%t A216307 Select[Range[800],Boole[PrimeQ[Range[10 #,10 #+9]]]=={0,0,0,1,0,0,0,0,0,1}&] (* _Harvey P. Dale_, Apr 23 2019 *)
%Y A216307 Cf. A032352, A007811, A078494.
%K A216307 nonn
%O A216307 1,1
%A A216307 _V. Raman_, Sep 03 2012