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A059694 Primes p such that 1p1, 3p3, 7p7 and 9p9 are all primes.

%I A059694 #20 Feb 23 2023 07:27:29
%S A059694 53,2477,4547,5009,7499,8831,9839,11027,24821,26393,29921,36833,46073,
%T A059694 46769,47711,49307,53069,59621,64283,66041,79901,84017,93263,115679,
%U A059694 133103,151121,169523,197651,207017,236807,239231,255191,259949,265271,270071,300431,330047
%N A059694 Primes p such that 1p1, 3p3, 7p7 and 9p9 are all primes.
%C A059694 All terms == 1 (mod 6). The sequence is apparently infinite. There are 16486 terms up to 10^9. - _Zak Seidov_, Jan 17 2014
%C A059694 Intersection of A069687, A069688, A069689, and A069690. - _Zak Seidov_, Jan 17 2014
%H A059694 Zak Seidov, <a href="/A059694/b059694.txt">Table of n, a(n) for n = 1..10000</a>
%e A059694 53 is a term because 1531, 3533, 7537 and 9539 are primes.
%o A059694 (Python)
%o A059694 from sympy import isprime, nextprime
%o A059694 from itertools import islice
%o A059694 def agen(): # generator of terms
%o A059694     p = 2
%o A059694     while True:
%o A059694         sp = str(p)
%o A059694         if all(isprime(int(d+sp+d)) for d in "1379"):
%o A059694             yield p
%o A059694         p = nextprime(p)
%o A059694 print(list(islice(agen(), 40))) # _Michael S. Branicky_, Feb 23 2023
%Y A059694 Cf. A059677, A032682, A059693.
%K A059694 nonn,base
%O A059694 1,1
%A A059694 _Patrick De Geest_, Feb 07 2001