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