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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.

A258214 Primes formed by concatenating p^2 with q, where p, q are consecutive primes.

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%I A258214 #13 Sep 08 2022 08:46:12
%S A258214 43,257,12113,84131,96137,168143,372167,32041181,120409349,139129379,
%T A258214 292681547,410881643,516961727,528529733,863041937,966289991,
%U A258214 10629611033,10670891039,11902811093,16307291279,21112091459,25058891597,29618411723,31933691789,35006411873
%N A258214 Primes formed by concatenating p^2 with q, where p, q are consecutive primes.
%C A258214 All the terms in this sequence, except a(1), are congruent to 2 (mod 3).
%H A258214 K. D. Bajpai, <a href="/A258214/b258214.txt">Table of n, a(n) for n = 1..10000</a>
%e A258214 a(2) = 257 is prime formed by concatenation of (5^2) = 25 with 7.
%e A258214 a(3) = 12113 is prime formed by concatenation of (11^2) = 121 with 13.
%t A258214 Select[Table[p = Prime[n]; FromDigits[Join[Flatten[ IntegerDigits[{p^2, NextPrime[p]}]]]], {n, 500}], PrimeQ]
%t A258214 Select[#[[1]]^2*10^IntegerLength[#[[2]]]+#[[2]]&/@Partition[Prime[ Range[ 300]],2,1],PrimeQ] (* _Harvey P. Dale_, Dec 05 2016 *)
%o A258214 (PARI) forprime(p = 1,5000, k=eval(concat( Str(p^2), Str(nextprime(p+1)) )); if(isprime(k), print1(k,", ")))
%o A258214 (Magma) [m: n in [1..300] | IsPrime(m) where m is Seqint(Intseq(NthPrime(n+1)) cat Intseq(NthPrime(n)^2))]; // _Vincenzo Librandi_, May 24 2015
%Y A258214 Cf. A000040, A030461, A030469.
%K A258214 nonn,base
%O A258214 1,1
%A A258214 _K. D. Bajpai_, May 23 2015