A020462 Primes that contain digits 3 and 5 only.

3, 5, 53, 353, 3533, 5333, 33353, 33533, 35353, 35533, 53353, 55333, 333533, 353333, 533353, 535333, 3335533, 3353333, 3353533, 3355553, 3533533, 3553553, 3555353, 5333353, 5333533, 5353553, 5533553, 33335333, 33555553, 35535553, 35553533

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Maple

sort(convert(`union`(seq(select(isprime, map(t -> 3*(10^d-1)/9 + 2*add(10^(s-1), s=t), combinat:-powerset(d))), d=0..10)), list)); # Robert Israel, Jul 21 2015

Mathematica

Flatten[Table[Select[FromDigits/@Tuples[{3, 5}, n], PrimeQ], {n, 8}]] (* Vincenzo Librandi, Jul 27 2012 *)

Prog

(Python)
from gmpy2 import is_prime, mpz
from itertools import product
A020462_list = [int(''.join(x)) for n in range(1, 10) for x in product('35', repeat=n) if is_prime(mpz(''.join(x)))] # Chai Wah Wu, Jul 21 2015

Crossrefs

Sequence in context: A355016 A260223 A260225 * A087602 A086340 A248923

Adjacent sequences: A020459 A020460 A020461 * A020463 A020464 A020465

Keyword

nonn,base

Author

David W. Wilson

Status

approved