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 A032625 #11 Jul 14 2015 01:12:36 %S A032625 13,79,911,2729,3739,4547,4951,5153,5557,6163,6971,7577,105107,109111, %T A032625 115117,117119,121123,151153,159161,181183,187189,195197,201203, %U A032625 211213,217219,225227,247249,271273,277279,285287,289291 %N A032625 Primes that are concatenations of n with n + 2. %C A032625 Or, primes which are the concatenation of two consecutive odd numbers. - _Parthasarathy Nambi_, Apr 11 2005 %e A032625 The first term is 13 which is a prime and is the concatenation of 1 and 3 - the first two odd numbers. %t A032625 lp = Range[1, 320, 2]; lst = {}; Do[p = FromDigits[ Join[ IntegerDigits[ lp[[n]]], IntegerDigits[ lp[[n + 1]] ]]]; If[ PrimeQ[p], AppendTo[lst, p]], {n, 159}]; lst (* _Robert G. Wilson v_, Apr 12 2005 *) %Y A032625 Cf. A032607, A032617. %K A032625 nonn,base %O A032625 1,1 %A A032625 _Patrick De Geest_, May 15 1998 %E A032625 Edited by _N. J. A. Sloane_, May 21 2008 at the suggestion of _R. J. Mathar_