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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.)