A261183 Primes having only {4, 7, 9} as digits.

7, 47, 79, 97, 449, 479, 499, 797, 947, 977, 997, 4447, 4799, 4999, 7477, 7499, 7949, 9479, 9497, 9749, 9949, 44449, 44497, 44777, 44797, 47497, 47777, 47779, 47797, 47947, 47977, 49477, 49499, 49747, 49999, 74449, 74747, 74779, 74797, 77447, 77477, 77479

Offset: 1

Author

Vincenzo Librandi, Aug 11 2015

Keywords

• nonn
• easy
• base

Comments

A020465, A020466 and A020471 are subsequences.

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..20000
• James Maynard and Brady Haran, Primes without a 7, Numberphile video (2019)
• Index to entries for primes with digits in a given set

Crossrefs

Cf. similar sequences listed in A261181.

Cf. A000040, A020465, A020466, A020471.

Programs

Magma

[p: p in PrimesUpTo(2*10^5) | Set(Intseq(p)) subset [4, 7, 9]];

Mathematica

Select[Prime[Range[6 10^4]], Complement[IntegerDigits[#], {4, 7, 9}] == {} &]