Numbers that are products of 4 primes (or 4-almost primes, a generalization of semiprimes).
16, 24, 36, 40, 54, 56, 60, 81, 84, 88, 90, 100, 104, 126, 132, 135, 136, 140, 150, 152
2 seqfan posts
Sat Feb 14 02:39:45 CET 2009 [seqfan] Re: Constants derived from Artin's constants