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

9049, 9631, 125329, 148249, 180289, 1000651, 1027591, 1250023, 1460479, 1674931, 1825891, 1889221, 3989683, 9003703, 9041143, 9049231, 10612219, 14499601, 14663479, 16333459, 18005983, 18428101, 90876631, 98087809, 98873821, 100720513, 100922011, 101274443, 108344311, 121623511, 123736969

Offset: 1

Author

J. M. Bergot and Robert Israel, Jun 17 2021

Keywords

• nonn
• base
• look

Examples

			a(3) = 125329 is a term because it is prime and its reversal 923521 = 31^4 where 31 is an emirp.
		

Crossrefs

Cf. A006567, A143260.

Programs

Maple

revdigs:= proc(n) local L,i; L:= convert(n,base,10); add(L[-i]*10^(i-1),i=1..nops(L)) end proc:
isemirp:= proc(n) local r; if not isprime(n) then return false fi;
r:= revdigs(n); r <> n and isprime(r) end proc:
E:= select(isemirp, [seq(i,i=11..10^5,2)]):
EP:= map(proc(x) local i; seq(x^i,i=2..floor(log[x](10^10))) end proc,E):
EPR:= map(revdigs,EP):
sort(select(isprime,EPR));