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%I #29 Sep 08 2022 08:44:45
%S 3,11,13,31,113,131,311,313,331,3313,3331,11113,11131,11311,13313,
%T 13331,31333,33113,33311,33331,113111,113131,131111,131113,131311,
%U 311111,313133,313331,313333,331333,333131,333331,1111333,1131113,1131131,1131133,1131331
%N Primes that contain digits 1 and 3 only.
%H Vincenzo Librandi, <a href="/A020451/b020451.txt">Table of n, a(n) for n = 1..1000</a>
%p N:= 8: # to get all a(n) with at most N digits
%p S:= {}:
%p for d from 1 to N do
%p r:= (10^d-1)/9;
%p S:= S union select(isprime,map(`+`,map(convert,combinat[powerset]
%p ({seq(2*10^i,i=0..d-1)}),`+`),r));
%p od:
%p S; # if using Maple 11 or earlier, uncomment the next line
%p # sort(convert(S,list)); # _Robert Israel_, May 04 2015
%t Flatten[Table[Select[FromDigits/@Tuples[{1,3},n],PrimeQ],{n,7}]] (* _Vincenzo Librandi_, Jul 27 2012 *)
%o (Magma) [p: p in PrimesUpTo(1131331) | Set(Intseq(p)) subset [1,3]];
%o // _Bruno Berselli_, Jul 27 2012
%o (Python)
%o from sympy import primerange
%o def checkd(a, c):
%o b = set(int(i) for i in set(str(a)))
%o return b.issubset(c)
%o for n in primerange(2, 2000000):
%o if checkd(n, [1, 3]):
%o print(n)
%o # _Abhiram R Devesh_, May 04 2015
%Y Subsequence of A045429.
%Y Subsequence of A032917.
%K nonn,base
%O 1,1
%A _David W. Wilson_
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