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 A239992 #12 Apr 08 2014 09:23:00 %S A239992 3637,576577,2433624337,3240032401,4410044101,6969669697,352836352837, %T A239992 404496404497,746496746497,16641001664101,17424001742401, %U A239992 20050562005057,20736002073601,24523562452357,26049962604997,28022762802277,34596003459601,35494563549457,42600964260097 %N A239992 Primes formed by concatenating a square number S with S+1, where S+1 is a prime number. %C A239992 It is observed that each term in the sequence ends either with digit 1 or 7. %H A239992 K. D. Bajpai, <a href="/A239992/b239992.txt">Table of n, a(n) for n = 1..1060</a> %e A239992 3637 is a prime formed by concatenaing 36 with 37 where 36= 6^2 and (36+1)= 37 is a prime. %e A239992 576577 is a prime formed by concatenaing 576 with 577 where 576= 24^2 and (576+1)= 577 is a prime. %p A239992 with(StringTools):KD := proc() local a,b,s;s:=n*n;b:=s+1; if isprime(b) then a:= parse(cat(s,b )); if isprime(a) then RETURN (a); fi; fi;end: seq(KD(), n=1..5000); %Y A239992 Cf. A000040, A030458. %K A239992 nonn,base %O A239992 1,1 %A A239992 _K. D. Bajpai_, Mar 30 2014