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 A180540 #11 Oct 30 2023 11:14:30
%S A180540 31,37,41,47,139,149,349,367,379,439,467,479,631,641,937,947,1039,
%T A180540 1049,1327,1381,1399,1427,1481,1499,2131,2141,2311,2347,2377,2411,
%U A180540 2437,2477,2539,2549,2731,2741,3001,3019,3079,3217,3229,3259,3271,3331,3449,3457
%N A180540 Primes that become a different prime under the mapping 3 <=> 4.
%H A180540 Robert Price, <a href="/A180540/b180540.txt">Table of n, a(n) for n = 1..1576</a>
%H A180540 <a href="/index/Pri#primes">Index to Primes</a>, Primes that become a different prime under some mapping.
%t A180540 fQ[n_] := Block[{id = IntegerDigits@n}, (MemberQ[id, 3] || MemberQ[id, 4]) && PrimeQ[ FromDigits[ id /. {3 -> 4, 4 -> 3}] ]]; Select[ Prime@ Range@ 500, fQ]
%Y A180540 Cf. A171022, A175791, A180517 thru A180559, A175789, A180560, A180561.
%K A180540 base,nonn
%O A180540 1,1
%A A180540 _Zak Seidov_ and _Robert G. Wilson v_, Sep 09 2010