A275276 a(n) = n! - p, where p is the third greatest prime less than n!.

6, 7, 4, 7, 13, 19, 19, 43, 29, 23, 43, 17, 67, 43, 71, 89, 239, 47, 197, 151, 43, 139, 197, 191, 239, 191, 173, 197, 47, 97, 223, 373, 71, 439, 307, 263, 157, 241, 199, 233, 337, 131, 179, 149, 113, 277, 269, 409, 197, 193, 379, 271, 181, 419, 367, 701, 751

Offset: 1

Author

Clark Kimberling, Jul 23 2016

Keywords

• nonn
• easy

Comments

Is every term except 4 and 6 a prime?

Examples

			For n = 4, we have n! = 24, so that p = 17, and a(4) = 7.
		

Links

• Clark Kimberling, Table of n, a(n) for n = 1..300

Crossrefs

Cf. A275272, A000040.

Programs

Mathematica

Table[n! - NextPrime[n!, -3], {n, 1, 150}]

Extensions

Name corrected by Pavel Irzhavski, Jul 25 2016