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A059694 Primes p such that 1p1, 3p3, 7p7 and 9p9 are all primes. 4
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified March 24 17:52 EDT 2023. Contains 361505 sequences. (Running on oeis4.)