A181564 Semiprime convenient numbers.

4, 6, 9, 10, 15, 21, 22, 25, 33, 57, 58, 85, 93, 133, 177, 253

Offset: 1

Author

Jonathan Vos Post, Jan 29 2011

Keywords

• nonn
• fini

Comments

This is to semiprimes A001358 as A140768 is to primes A000040. Because Euler's "numerus idoneus" (idoneal, or suitable, or convenient numbers) are finite, this subset is finite. Conjecture: this list is complete (see Weinberger's result and comment by Jud McCranie in A140768).

Examples

			a(16) = A000926(50) = 253 = 11 * 23.
		

Crossrefs

Cf. A001358, A140768.

Formula

A000926 INTERSECTION A001358.