A289553 - OEIS

%I #14 Sep 08 2022 08:46:19

%S 1,4,8,9,12,16,18,20,24,25,27,28,30,32,36,40,42,44,45,48,49,50,52,54,

%T 56,60,63,64,66,68,70,72,75,76,78,80,81,84,88,90,92,96,98,99,100,102,

%U 104,105,108,110,112,114,116,117,120,121,124,125,126,128,130,132

%N Numbers that are not the product of two distinct noncomposite numbers (A008578).

%C Numbers k such that tau(k) = A000005(k) is not equal to 2*omega(k) = 2*A001221(k).

%e Number 6 is not in the sequence because 6 = 2 * 3.

%o (Magma) [n: n in [1..1000] | NumberOfDivisors(n) ne 2*#PrimeDivisors(n)]

%Y Complement of A167171.

%Y Cf. A246716 (with two distinct primes), A008578 (with two distinct nonprimes), A289555 (with two distinct composites).

%K nonn

%O 1,2

%A _Jaroslav Krizek_, Jul 07 2017