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Primes that contain digits 3 and 4 only.
13

%I #12 Sep 08 2022 08:44:45

%S 3,43,433,443,3343,3433,33343,333433,334333,343333,343433,444343,

%T 444443,3333433,3343343,3343433,3344333,3344443,3433333,3434443,

%U 3443443,3444443,4344443,4433333,4434343,4443433,34333333,34434343,34444343,43444433

%N Primes that contain digits 3 and 4 only.

%H Vincenzo Librandi, <a href="/A020461/b020461.txt">Table of n, a(n) for n = 1..1000</a>

%t Flatten[Table[Select[FromDigits/@Tuples[{3,4},n],PrimeQ],{n,8}]] (* _Vincenzo Librandi_, Jul 27 2012 *)

%o (Magma) [p: p in PrimesUpTo(43444433) | Set(Intseq(p)) subset [3,4]];

%o // _Bruno Berselli_, Jul 27 2012

%Y Cf. A054356.

%K nonn,base

%O 1,1

%A _David W. Wilson_