A364831 Primes whose digits are prime and in nonincreasing order.

2, 3, 5, 7, 53, 73, 733, 773, 5333, 7333, 7753, 55333, 75533, 75553, 77773, 733333, 755333, 775553, 7553333, 7555333, 7775533, 7777753, 55555333, 55555553, 77755553, 555553333, 755555533, 773333333, 777555553, 777773333, 777775333, 777775553, 777777773

Offset

1,1

Comments

Intersection of A028867 and A019546.

The subsequence for primes whose digits are prime and in strictly decreasing order has just six terms: 2 3 5 7 53 73 (see A177061).

Links

Chai Wah Wu, Table of n, a(n) for n = 1..10000

Mathematica

Select[Prime[Range[3100000]], AllTrue[d = IntegerDigits[#], PrimeQ] && GreaterEqual @@ d &]

Prog

(Python)
from itertools import count, islice, chain, combinations_with_replacement
from sympy import isprime
def A364831_gen(): # generator of terms
    yield 2
    yield from chain.from_iterable((sorted(s for d in combinations_with_replacement('753', l) if isprime(s:=int(''.join(d)))) for l in count(1)))
A364831_list = list(islice(A364831_gen(), 30)) # Chai Wah Wu, Sep 10 2023

Crossrefs

Cf. A009996, A019546, A177061, A028867.

Sequence in context: A214179 A178237 A118842 * A244595 A244597 A237439

Adjacent sequences: A364828 A364829 A364830 * A364832 A364833 A364834

Keyword

nonn,base

Author

James C. McMahon, Aug 09 2023

Status

approved