A103545 Largest n-digit zeroless prime with nonprime digits.

89, 991, 9949, 99991, 999961, 9999991, 99999989, 999999491, 9999999881, 99999999689, 999999999989, 9999999999161, 99999999999481, 999999999999989, 9999999999999641, 99999999999999961, 999999999999999989, 9999999999999999961, 99999999999999999989

Offset: 2

Author

Ray G. Opao, Mar 22 2005

Keywords

• base
• nonn

Links

• Michael S. Branicky, Table of n, a(n) for n = 2..1000

Crossrefs

Cf. A103544.

Programs

Mathematica

PrevPrim[n_] := Block[{k = n - 1}, While[ !PrimeQ[k], k-- ]; k]; f[n_] := Block[{pp = PrevPrim[ 10^n]}, While[ Union[ Join[{1, 4, 6, 8, 9}, IntegerDigits[pp]]] != {1, 4, 6, 8, 9}, pp = PrevPrim[pp]]; pp]; Table[ f[n], {n, 2, 18}] (* Robert G. Wilson v, Mar 26 2005 *)

Python

from sympy import isprime
from itertools import product
def a(n):
    for p in product("98641", repeat=n):
        t = int("".join(p))
        if isprime(t): return t
print([a(n) for n in range(2, 22)]) # Michael S. Branicky, Aug 10 2022

Extensions

More terms from Jonathan Vos Post, Mar 23 2005

a(7) to a(12) from Jonathan Vos Post, Mar 23 2005

a(13) to a(18) from Robert G. Wilson v, Mar 26 2005

a(19) and beyond from Michael S. Branicky, Aug 10 2022