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 A174034 #15 Feb 20 2023 05:18:54
%S A174034 3,3,7,19,17,7,17,7,3,23,11,11,11,17,3,3,7,3,11,17,29,19,13,7,37,7,23,
%T A174034 37,7,23,7,7,7,11,7,53,29,31,31,13,11,17,7,11,11,29,23,47,7,7,7,13,11,
%U A174034 19,67,19,13,101,59,13,13,31,17,23,7,13,29,73,29,7
%N A174034 The smallest prime p such that the double-concatenation prime(n) // prime(n+1) // p is a prime number.
%C A174034 It is conjectured that a(n) = 3 for infinitely many n.
%e A174034 n=1: 2 // 3 // 3 = 233, which is prime, so a(1) = 3.
%e A174034 n=2: 3 // 5 // 2 = 352, which is not prime, but 3 // 5 // 3 = 353 is, so a(2) = 3.
%o A174034 (Sage)
%o A174034 concat = lambda xx: Integer(''.join(map(str,xx)))
%o A174034 A174034 = lambda x: next((p for p in Primes() if is_prime(concat([nth_prime(x), nth_prime(x+1), p])))) # _D. S. McNeil_, Dec 02 2010
%o A174034 (PARI) A174034(n)={ n=eval(Str(prime(n),prime(n+1))); for( d=1,99, n*=10; forprime( p=10^(d-1),10^d, isprime(n+p) & return(p)))} \\ _M. F. Hasler_, Dec 01 2010
%Y A174034 Cf. A030461, A030459, A030469, A171154, A174031
%K A174034 base,nonn
%O A174034 1,1
%A A174034 Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Mar 06 2010
%E A174034 Edited and terms checked by _D. S. McNeil_, Dec 01 2010