Numbers that are products of 4 primes.

Terms

a(0) =16a(1) =24a(2) =36a(3) =40a(4) =54a(5) =56a(6) =60a(7) =81a(8) =84a(9) =88a(10) =90a(11) =100a(12) =104a(13) =126a(14) =132a(15) =135a(16) =136a(17) =140a(18) =150a(19) =152a(20) =156a(21) =184a(22) =189a(23) =196a(24) =198a(25) =204a(26) =210a(27) =220a(28) =225a(29) =228