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 A178317 #2 Mar 31 2012 10:26:32 %S A178317 2,3,5,11,13,23,31,53,83,101,103,113,131,181,251,311,313,331,383,521, %T A178317 811,823,853,881,883,1013,1021,1031,1033,1051,1103,1123,1153,1181, %U A178317 1223,1231,1283,1301,1303,1381,1531,1553,1583,1801,1811,1831,2003,2011,2053 %N A178317 Primes with the property that if the digits are written digital clock style and the number is reflected across a horizontal line through the middle of the number, the result is still prime. %e A178317 For example when 251 is reflected it becomes 521 which is also a prime, but a different one. %Y A178317 Cf. A018847. %K A178317 nonn,base %O A178317 1,1 %A A178317 _David Nacin_, May 24 2010