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 A180541 #10 Jul 28 2020 11:07:35 %S A180541 3,5,131,137,151,157,337,347,547,557,839,859,1031,1051,1367,1439,1459, %T A180541 1567,1637,1657,1931,1951,2351,2531,2837,2857,3011,3119,3167,3209, %U A180541 3251,3257,3301,3307,3319,3391,3407,3449,3457,3547,3581,3631,3637,3659,3701 %N A180541 Primes that become a different prime under the mapping 3 <=> 5. %H A180541 Robert Israel, <a href="/A180541/b180541.txt">Table of n, a(n) for n = 1..10000</a> %H A180541 <a href="/index/Pri#primes">Index to Primes</a>, Primes that become a different prime under some mapping. %p A180541 filter:= proc(n) local L,Lp,i,x; %p A180541 if not isprime(n) then return false fi; %p A180541 L:= convert(n,base,10); %p A180541 Lp:= subs([3=5,5=3],L); %p A180541 if L=Lp then return false fi; %p A180541 isprime(add(Lp[i]*10^(i-1),i=1..nops(Lp))) %p A180541 end proc: %p A180541 select(filter, [seq(i,i=3..10000,2)]); # _Robert Israel_, Jul 28 2020 %t A180541 fQ[n_] := Block[{id = IntegerDigits@n}, (MemberQ[id, 3] || MemberQ[id, 5]) && PrimeQ[ FromDigits[ id /. {3 -> 5, 5 -> 3}] ]]; Select[ Prime@ Range@ 550, fQ] %Y A180541 Cf. A171026, A175791, A180517 thru A180559, A175789, A180560, A180561. %K A180541 base,nonn %O A180541 1,1 %A A180541 _Zak Seidov_ and _Robert G. Wilson v_, Sep 09 2010