A081027 Primes that are not in A080608.

11, 19, 41, 61, 89, 101, 109, 149, 151, 181, 191, 199, 211, 227, 241, 251, 257, 277, 281, 349, 389, 401, 409, 419, 421, 449, 461, 491, 499, 521, 541, 557, 577, 587, 601, 619, 641, 661, 691, 727, 757, 787, 809, 811, 821, 827, 857, 877, 881, 887, 911, 919, 941

Offset: 1

Author

David W. Wilson, Mar 02 2003

Keywords

• nonn
• base

Comments

Repeated removal of a single digit must eventually result in a nonprime.

Undeletable primes. - Arkadiusz Wesolowski, Oct 18 2011

Links

• Michael S. Branicky, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A080608.

Programs

Python

from sympy import isprime, prevprime
def c(n):
    if not isprime(n): return False
    if n < 10: return True
    s = str(n)
    si = (s[:i]+s[i+1:] for i in range(len(s)))
    return any(t[0] != '0' and c(int(t)) for t in si)
def ok(n):
    return isprime(n) and not c(n)
print([k for k in range(942) if ok(k)]) # Michael S. Branicky, Jan 27 2023