Numerator of the harmonic mean of the first n positive integers.

Terms

a(0) =1a(1) =4a(2) =18a(3) =48a(4) =300a(5) =120a(6) =980a(7) =2240a(8) =22680a(9) =25200a(10) =304920a(11) =332640a(12) =4684680a(13) =5045040a(14) =5405400a(15) =11531520a(16) =208288080a(17) =73513440a(18) =1474352880a(19) =62078016a(20) =108636528a(21) =113809696a(22) =2736605872a(23) =8566766208a(24) =223092870000a(25) =232016584800