A199347 Primes having only {3, 4, 7} as digits.

3, 7, 37, 43, 47, 73, 337, 347, 373, 433, 443, 733, 743, 773, 3343, 3347, 3373, 3433, 3733, 4337, 4373, 4447, 4733, 7333, 7433, 7477, 33343, 33347, 33377, 33773, 34337, 34747, 37337, 37447, 37747, 43777, 44773, 44777, 47737, 47743, 47777, 73433, 73477, 74377, 74747, 77347, 77377, 77447, 77477, 77743

Offset: 1

Author

M. F. Hasler, Nov 05 2011

Keywords

• nonn
• base

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..10000
• Index to entries for primes with digits in a given set

Crossrefs

Cf. A020449 - A020472, A199325 - A199329.

Programs

Mathematica

Select[Flatten[Table[FromDigits/@Tuples[{3,4,7},n],{n,5}]],PrimeQ] (* Harvey P. Dale, Jul 31 2012 *)

PARI

a(n, list=0, L=[3, 4, 7], reqpal=0)={my(t); for(d=1, 1e9, u=vector(d, i, 10^(d-i))~; forvec(v=vector(d, i, [1+(i==1&!L[1]), #L]), isprime(t=vector(d, i, L[v[i]])*u) || next; reqpal & !isprime(A004086(t)) & next; list & print1(t", "); n--||return(t)))}