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%I #14 Sep 08 2022 08:44:45
%S 11,61,661,6661,11161,16111,16661,66161,111611,161611,611111,616111,
%T 1111661,1611161,1616161,1616611,1661111,1661161,1666111,6111661,
%U 6116111,6116161,6161161,6611611,6661111,6661661,11111161,11166611,11616611
%N Primes that contain digits 1 and 6 only.
%H Vincenzo Librandi, <a href="/A020454/b020454.txt">Table of n, a(n) for n = 1..1000</a>
%t Flatten[Table[Select[FromDigits/@Tuples[{1,6},n],PrimeQ],{n,8}]] (* _Vincenzo Librandi_, Jul 27 2012 *)
%t Select[Flatten[Table[10*FromDigits/@Tuples[{1,6},n]+1,{n,7}]],PrimeQ] (* Slightly faster than the above Mathematica program by forcing the last digit to be one. *) (* _Harvey P. Dale_, May 31 2018 *)
%o (Magma) [p: p in PrimesUpTo(11616611) | Set(Intseq(p)) subset [1, 6]]; // _Vincenzo Librandi_, Jul 27 2012. (see Berselli A020461).
%K nonn,base
%O 1,1
%A _David W. Wilson_
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