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A217614 Emirps p such that the next emirp is equal to the next prime.

%I A217614 #23 Jun 20 2021 17:25:20
%S A217614 13,31,71,73,337,701,733,739,743,761,937,953,967,983,1021,1031,1097,
%T A217614 1103,1151,1193,1201,1213,1217,1223,1229,1231,1237,1249,1279,1381,
%U A217614 1399,1499,1511,1583,1597,1723,1733,1831,1933,3011,3019,3083,3089,3191,3271,3299
%N A217614 Emirps p such that the next emirp is equal to the next prime.
%H A217614 Robert Israel, <a href="/A217614/b217614.txt">Table of n, a(n) for n = 1..10000</a>
%e A217614 13 is in the sequence because the next emirp (17) is also the next prime.
%e A217614 71 is in the sequence because the next emirp (73) is also the next prime.
%p A217614 digrev:= proc(n) local L,i;
%p A217614  L:= convert(n,base,10);
%p A217614  add(L[-i]*10^(i-1),i=1..nops(L))
%p A217614 end proc:
%p A217614 isemirp:= proc(n) local r;
%p A217614   r:= digrev(n);
%p A217614   r <> n and isprime(r)
%p A217614 end proc:
%p A217614 R:= NULL: count:= 0:
%p A217614 p:= 2: ep:= false:
%p A217614 while count < 100 do
%p A217614   q:= p; eq:= ep;
%p A217614   p:= nextprime(p);
%p A217614   ep:= isemirp(p);
%p A217614   if ep and eq then
%p A217614      R:= R, q; count:= count+1;
%p A217614   fi
%p A217614 od:
%p A217614 R; # _Robert Israel_, Jun 20 2021
%t A217614 emirpQ[n_] := PrimeQ[n] && Block[{r=FromDigits@Reverse@IntegerDigits@n},
%t A217614 r != n && PrimeQ[r]]; nextEmirp[n_] := Block[{e=NextPrime[n]}, While[! emirpQ[e], e = NextPrime[e]]; e]; Select[Prime@Range@1000, emirpQ[#] && NextPrime[#] == nextEmirp[#] &] (* _Giovanni Resta_, Oct 28 2012 *)
%Y A217614 Cf. A000040, A006567.
%K A217614 nonn,base,easy
%O A217614 1,1
%A A217614 _Jonathan Vos Post_, Oct 08 2012
%E A217614 More terms from _Giovanni Resta_, Oct 28 2012