A289555 Numbers that are not the product of two distinct composite numbers (A002808).

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31, 33, 34, 35, 37, 38, 39, 41, 42, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 55, 57, 58, 59, 61, 62, 63, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77

Offset: 1

Author

Jaroslav Krizek, Jul 07 2017

Keywords

• nonn

Examples

			Number 24 is not in the sequence because 24 = 4 * 6.
		

Crossrefs

Complement of A289554.

Cf. A246716 (with two distinct primes), A008578 (with two distinct nonprimes), A289553 (with two distinct noncomposites).

Programs

Magma

[n: n in [1..1000] | (#PrimeDivisors(n) eq 1 and NumberOfDivisors(n) lt 6) or (#PrimeDivisors(n) eq 2 and NumberOfDivisors(n) lt 8) or (#PrimeDivisors(n) ge 3 and NumberOfDivisors(n) lt 12) ];