A281093 Primes having only {3, 4, 7, 9} as digits.

3, 7, 37, 43, 47, 73, 79, 97, 337, 347, 349, 373, 379, 397, 433, 439, 443, 449, 479, 499, 733, 739, 743, 773, 797, 937, 947, 977, 997, 3343, 3347, 3373, 3433, 3449, 3499, 3733, 3739, 3779, 3793, 3797, 3943, 3947, 4337, 4339, 4349, 4373, 4397, 4447, 4493, 4733

Offset: 1

Author

Bobby Jacobs, Jan 24 2017

Keywords

• base
• nonn

Comments

The Fibonacci prime 433494437 is in this sequence.

These are primes that only use digits that survived in the movie 9: {3, 4, 7, 9}.

Links

• Jason Bard, Table of n, a(n) for n = 1..10000
• Wikipedia, 9 (2009 animated film)
• Index to entries for primes with digits in a given set

Crossrefs

Cf. A091633.

Programs

PARI

is(n)=#setunion(Set(digits(n)), [3,4,7,9])==4 && isprime(n) \\ Charles R Greathouse IV, Jan 24 2017

Formula

a(n) >> n^k, where k = log(10)/log(4) = 1.660964.... - Charles R Greathouse IV, Jan 24 2017