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

53, 2477, 4547, 5009, 7499, 8831, 9839, 11027, 24821, 26393, 29921, 36833, 46073, 46769, 47711, 49307, 53069, 59621, 64283, 66041, 79901, 84017, 93263, 115679, 133103, 151121, 169523, 197651, 207017, 236807, 239231, 255191, 259949, 265271, 270071, 300431, 330047

Offset

1,1

Comments

All terms == 1 (mod 6). The sequence is apparently infinite. There are 16486 terms up to 10^9. - Zak Seidov, Jan 17 2014

Intersection of A069687, A069688, A069689, and A069690. - Zak Seidov, Jan 17 2014

Links

Zak Seidov, Table of n, a(n) for n = 1..10000

Example

53 is a term because 1531, 3533, 7537 and 9539 are primes.

Prog

(Python)
from sympy import isprime, nextprime
from itertools import islice
def agen(): # generator of terms
    p = 2
    while True:
        sp = str(p)
        if all(isprime(int(d+sp+d)) for d in "1379"):
            yield p
        p = nextprime(p)
print(list(islice(agen(), 40))) # Michael S. Branicky, Feb 23 2023

Crossrefs

Cf. A059677, A032682, A059693.

Sequence in context: A282931 A210783 A221237 * A263516 A243231 A280357

Adjacent sequences: A059691 A059692 A059693 * A059695 A059696 A059697

Keyword

nonn,base

Author

Patrick De Geest, Feb 07 2001

Status

approved