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%I #19 Sep 08 2022 08:44:45
%S 11,19,191,199,911,919,991,1999,9199,11119,19919,19991,91199,99119,
%T 99191,99991,111119,111191,111919,119191,191119,191911,191999,199999,
%U 911111,919111,991999,999199,1111991,1191119,1191191,1191199,1191991,1199999
%N Primes that contain digits 1 and 9 only.
%H Alois P. Heinz, <a href="/A020457/b020457.txt">Table of n, a(n) for n = 1..20000</a> (first 1000 terms from Vincenzo Librandi)
%H James Maynard and Brady Haran, <a href="https://www.youtube.com/watch?v=eeoBCS7IEqs">Primes without a 7</a>, Numberphile video (2019)
%t Flatten[Table[Select[FromDigits/@Tuples[{1,9},n],PrimeQ],{n,7}]] (* _Vincenzo Librandi_, Jul 27 2012 *)
%o (Magma) [p: p in PrimesUpTo(1199999) | Set(Intseq(p)) subset [1, 9]]; // _Vincenzo Librandi_, Jul 27 2012
%Y Cf. A329761.
%K nonn,base
%O 1,1
%A _David W. Wilson_
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