a(n) is the least number with exactly n divisors of the form 4*k+3.

Terms

a(0) =1a(1) =3a(2) =15a(3) =63a(4) =105a(5) =567a(6) =315a(7) =3969a(8) =945a(9) =1575a(10) =2835a(11) =413343a(12) =3465a(13) =53361a(14) =19845a(15) =14175a(16) =10395a(17) =1750329a(18) =17325a(19) =26040609a(20) =31185a(21) =99225a(22) =480249a(23) =219667417263a(24) =45045a(25) =354375a(26) =266805a(27) =121275a(28) =257985a(30) =155925