A289554 Numbers that are the product of two distinct composite numbers (A002808).

24, 32, 36, 40, 48, 54, 56, 60, 64, 72, 80, 84, 88, 90, 96, 100, 104, 108, 112, 120, 126, 128, 132, 135, 136, 140, 144, 150, 152, 156, 160, 162, 168, 176, 180, 184, 189, 192, 196, 198, 200, 204, 208, 210, 216, 220, 224, 225, 228, 232, 234, 240, 243, 248, 250

Offset

1,1

Links

Table of n, a(n) for n=1..55.

Example

Number 24 is in the sequence because 24 = 4 * 6.

Prog

(Magma) [n: n in [1..1000] | (#PrimeDivisors(n) eq 1 and NumberOfDivisors(n) ge 6) or (#PrimeDivisors(n) eq 2 and NumberOfDivisors(n) ge 8) or (#PrimeDivisors(n) ge 3 and NumberOfDivisors(n) ge 12) or (#PrimeDivisors(n) ge 4)]

Crossrefs

Complement of A289555.

Cf. A006881 (with two distinct primes), A002808 (with two distinct nonprimes), A167171 (with two distinct noncomposites).

Sequence in context: A337055 A064673 A034782 * A334589 A334936 A102374

Adjacent sequences: A289551 A289552 A289553 * A289555 A289556 A289557

Keyword

nonn

Author

Jaroslav Krizek, Jul 07 2017

Status

approved