A199347 Primes having only the (decimal) digits 3, 4 and 7.

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

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..10000

Index to entries for primes with digits in a given set

Mathematica

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

Prog

(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)))}

Crossrefs

Cf. A020449 - A020472, A199325 - A199329.

Sequence in context: A167169 A269995 A281093 * A252795 A049493 A260380

Adjacent sequences: A199344 A199345 A199346 * A199348 A199349 A199350

Keyword

nonn,base

Author

M. F. Hasler, Nov 05 2011

Status

approved