cp's OEIS Frontend

A345389 Primes that are not emirps but whose digit reversal is a power of an emirp.

%I A345389 #12 Jun 18 2021 12:24:19
%S A345389 9049,9631,125329,148249,180289,1000651,1027591,1250023,1460479,
%T A345389 1674931,1825891,1889221,3989683,9003703,9041143,9049231,10612219,
%U A345389 14499601,14663479,16333459,18005983,18428101,90876631,98087809,98873821,100720513,100922011,101274443,108344311,121623511,123736969
%N A345389 Primes that are not emirps but whose digit reversal is a power of an emirp.
%e A345389 a(3) = 125329 is a term because it is prime and its reversal 923521 = 31^4 where 31 is an emirp.
%p A345389 revdigs:= proc(n) local L,i; L:= convert(n,base,10); add(L[-i]*10^(i-1),i=1..nops(L)) end proc:
%p A345389 isemirp:= proc(n) local r; if not isprime(n) then return false fi;
%p A345389 r:= revdigs(n); r <> n and isprime(r) end proc:
%p A345389 E:= select(isemirp, [seq(i,i=11..10^5,2)]):
%p A345389 EP:= map(proc(x) local i; seq(x^i,i=2..floor(log[x](10^10))) end proc,E):
%p A345389 EPR:= map(revdigs,EP):
%p A345389 sort(select(isprime,EPR));
%Y A345389 Cf. A006567, A143260.
%K A345389 nonn,base,look
%O A345389 1,1
%A A345389 _J. M. Bergot_ and _Robert Israel_, Jun 17 2021