A059677 -id:A059677 - cp's OEIS frontend

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

Patrick De Geest, Feb 07 2001

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

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

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

Cf. A059677, A032682, A059693.

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

A059693 Palindromes n such that 1n1, 3n3, 7n7 and 9n9 are all primes.

Original entry on oeis.org

8179718, 8615168, 209484902, 303272303, 342272243, 354050453, 378707873, 533373335, 631363136, 661525166, 668787866, 792545297, 807989708, 964666469, 12792529721, 14435153441, 17755355771, 20160806102, 20175857102

Offset: 1

Patrick De Geest, Feb 07 2001

			8179718 is ok because 181797181, 381797183, 781797187 and 981797189 are primes.

Chai Wah Wu, Table of n, a(n) for n = 1..2878

Cf. A059677, A032682, A059694.

cp's OEIS Frontend

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

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