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A345528 a(n) is the first prime that begins a sequence of exactly n consecutive primes that are emirps.

%I A345528 #18 Jun 29 2021 02:33:41
%S A345528 97,13,71,733,3371,10039,11897,334759,7904639,1193,1477271183,
%T A345528 9387802769,15423094826093
%N A345528 a(n) is the first prime that begins a sequence of exactly n consecutive primes that are emirps.
%C A345528 The prime before a(n) is not an emirp, the n consecutive primes starting with a(n) are emirps, and the next prime is not an emirp.
%C A345528 a(n) > 2*10^8 for n > 10.
%e A345528 a(3) = 71 because the 3 consecutive primes 71, 73, 79 are emirps while the previous and next primes 67 and 83 are not emirps.
%p A345528 digrev:= proc(n) local L,i;
%p A345528 L:= convert(n,base,10);
%p A345528 add(L[-i]*10^(i-1),i=1..nops(L))
%p A345528 end proc:
%p A345528 isemirp:= proc(n) local r;
%p A345528   r:= digrev(n);
%p A345528   r <> n and isprime(r)
%p A345528 end proc:
%p A345528 V:= Vector(10): count:= 0:
%p A345528 p:= 2: ep:= 0: q:= 2:
%p A345528 while count < 10 do
%p A345528   p:= nextprime(p);
%p A345528   flag:= isemirp(p);
%p A345528   if flag then
%p A345528     if ep = 0 then q:= p fi;
%p A345528     ep:= ep+1;
%p A345528   else
%p A345528     if ep > 0 then
%p A345528       if ep <=  10 and V[ep] = 0 then
%p A345528          count:= count+1; V[ep]:= q;
%p A345528       fi;
%p A345528     fi;
%p A345528     ep:= 0;
%p A345528   fi
%p A345528 od:
%p A345528 convert(V,list);
%Y A345528 Cf. A006567, A071612, A217614.
%K A345528 nonn,more,base
%O A345528 1,1
%A A345528 _J. M. Bergot_ and _Robert Israel_, Jun 20 2021
%E A345528 a(11)-a(12) from _Daniel Suteu_, Jun 21 2021
%E A345528 a(13) from _Martin Ehrenstein_, Jun 28 2021