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Primes that contain only the digits (2, 5, 7).
2

%I #14 Sep 08 2022 08:46:02

%S 2,5,7,227,257,277,557,577,727,757,2557,2777,5227,5527,5557,7577,7727,

%T 7757,22277,22727,22777,25577,27277,27527,52727,52757,57527,57557,

%U 57727,72227,72277,72577,72727,75227,75277,75527,75557,75577,77527,77557,222527,222557

%N Primes that contain only the digits (2, 5, 7).

%C The digits are prime numbers.

%H Vincenzo Librandi, <a href="/A214705/b214705.txt">Table of n, a(n) for n = 1..1000</a>

%t Flatten[Table[Select[FromDigits/@Tuples[{2,5,7},n],PrimeQ],{n,6}]]

%o (Magma) [p: p in PrimesUpTo(100000) | Set(Intseq(p)) subset [2,5,7]];

%o (Python)

%o from sympy import primerange

%o def ok(p): return set(str(p)) <= set("257")

%o def aupto(limit): return [p for p in primerange(2, limit+1) if ok(p)]

%o print(aupto(222557)) # _Michael S. Branicky_, Feb 05 2021

%Y Subsequence of A019546.

%K nonn,base,easy

%O 1,1

%A _Vincenzo Librandi_, Jul 28 2012