A052424 Numbers k with no single-digit factors (apart from 1 and k).

1, 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 121, 127, 131, 137, 139, 143, 149, 151, 157, 163, 167, 169, 173, 179, 181, 187, 191, 193, 197, 199, 209, 211, 221, 223, 227, 229, 233, 239

Offset: 1

Author

Henry Bottomley, Mar 14 2000

Keywords

• nonn
• base

Crossrefs

Cf. A008364.

Programs

PARI

isok(n) = {d = divisors(n); for (i = 2, #d - 1,if (length(Str(d[i])) == 1, return (0));); return (1);} \\ Michel Marcus, Jul 27 2013