A346028 Primes that are the first in a run of exactly 8 emirps.

334759, 9094009, 9685771, 11875307, 12503017, 19776443, 32906869, 35414443, 37376201, 70252333, 71161309, 73694129, 77454067, 93907523, 98606489, 100545637, 104827991, 112604857, 147009703, 155376791, 183766217, 187717499, 194024953, 196702423, 314716411

Offset: 1

Author

Lars Blomberg, Jul 14 2021

Keywords

• nonn
• base

Comments

There are large gaps in this sequence because all terms need to begin with 1, 3, 7, or 9 otherwise the reversal is composite.

Examples

			a(1) = 334759 because of the 10 consecutive primes 334753, 334759, 334771, 334777, 334783, 334787, 334793, 334843, 334861, 334877 all except 334753 and 334877 are emirps and this is the first such occurrence.
		

Crossrefs

Subsequence of A006567 (emirps).

Cf. A003684, A048052, A048054, A071612, A346022, A346023, A346024, A346025, A346026, A346027.

Programs

Mathematica

EmQ[n_]:=(s=IntegerReverse@n;PrimeQ@s&&n!=s);
Monitor[Do[p=Prime@k;If[MemberQ[{1,3,7,9},First@IntegerDigits@p],If[Boole[EmQ/@NextPrime[p,Range[-1,8]]]=={0,1,1,1,1,1,1,1,1,0},Print@p]],{k,10^6}],p] (* Giorgos Kalogeropoulos, Jul 27 2021 *)

Python

# uses code in A346026
print(aupto(10**7, runlength=8)) # Michael S. Branicky, Jul 14 2021