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 A125524 #16 May 26 2019 04:39:34
%S A125524 13,17,43,47,67,83,97,103,107,113,127,137,157,163,167,173,193,197,433,
%T A125524 443,457,463,467,487,607,613,617,643,647,653,673,677,683,823,827,853,
%U A125524 857,863,877,883,887,907,937,947,953,967,977,983,997,1013,1019,1031
%N A125524 Republican primes: primes such that the right half of the prime is prime and the left half is not.
%C A125524 If the length of n is odd then the central number is not used in the calculation. So neither the left half nor the right half will contain the central digit. If the length of n is even, then all numbers are used.
%H A125524 Tony Padilla and Brady Haran, <a href="https://www.youtube.com/watch?v=zk_Q9y_LNzg">The Most Evil Number</a>, Numberphile video (2018)
%e A125524 The right half of 13 is 3, which is prime. The left half is 1, which is not prime.
%e A125524 The right half of 113 is 3, which is prime. The left half is 1, which is not prime.
%o A125524 (PARI) /* Political primes, republican case. */ rep(n) = { local(x,ln,y,lp,rp); forprime(x=2,n, y=Str(x); if(x > 9, ln=floor(length(y)/2), ln=1); lp = eval(left(y,ln)); rp = eval(right(y,ln)); if(!isprime(lp)&& isprime(rp),print1(x",") ) ) }
%Y A125524 Cf. A125523, A125525.
%K A125524 base,easy,nonn
%O A125524 2,1
%A A125524 _Cino Hilliard_, Jan 22 2007