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 A233385 #14 Mar 13 2015 18:50:11 %S A233385 23,37,7127,138191,19524287 %N A233385 Primes that are a concatenations of n-th Mersenne exponent and n-th Mersenne prime. %C A233385 Primes of the form A000043(n)*10^A028335(n) + A000668(n). %e A233385 a(4) is 138191(prime number) where 13 is 5th Mersenne exponent and 8191 is 5th Mersenne prime. %Y A233385 Cf. A000043, A000668, A028335. %K A233385 nonn,base,less %O A233385 1,1 %A A233385 _Juri-Stepan Gerasimov_, Dec 08 2013