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 A233358 #11 Dec 09 2013 13:44:17 %S A233358 2,6,30,32,38,48,50,72,90,92,98,102,110,126,128,150,182,188,212,218, %T A233358 230,242,258,300,318,348,398,420,440,450,462,498,516,518,530,542,572, %U A233358 582,636,660,662,678,702,716,726,728,746,786,798,830,848,872,878,890,908 %N A233358 Numbers n such that n^2 concatenated with n + 1 is prime. %C A233358 All the terms in sequence are even numbers, but none are congruent to 4 mod 10. %H A233358 K. D. Bajpai, <a href="/A233358/b233358.txt">Table of n, a(n) for n = 1..5550</a> %e A233358 6 is in the sequence because the concatenation of 6^2 and 6 + 1 gives 367, which is prime. %e A233358 30 is in the sequence because the concatenation of 30^2 and 31 gives 90031, which is prime. %e A233358 34 is not in the sequence because the concatenation of 34^2 and 35 gives 115635 = 3 * 5 * 13 * 593. %p A233358 KD := proc() local a,b; a:=parse(cat(n^2,n+1)); if isprime(a) then RETURN (n); fi; end: seq(KD(), n=1..2000); %Y A233358 Cf. A030465 (numbers n: concatenate n with n + 1 is prime). %K A233358 nonn,base,less %O A233358 1,1 %A A233358 _K. D. Bajpai_, Dec 07 2013