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 A088712 #1 Feb 19 2004 03:00:00 %S A088712 5,53,59,67,137,179,211,223,239,263,359,541,593,613,631,653,659,757, %T A088712 809,977,997,1009,1109,1129,1237,1399,1559,1783,1931,1979,1993,2309, %U A088712 2339,2347,2411,2683,2879,3061,3203,3271,3613,3643,3767,4001 %N A088712 Primes which when concatenated with the previous prime form a new prime. %F A088712 If isprime(p(n) & p(n-1)) then sequence.add(p(n)) %e A088712 a(2) = 53 because 53 concatenated with the preceding prime (47) yields 5347 which is also prime. %Y A088712 Cf. A088784. %K A088712 base,nonn %O A088712 1,1 %A A088712 Chuck Seggelin (barkeep(AT)plasteredDragon.com), Oct 15 2003