Quadruples of different integers from [ 2,n ] with no global factor.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =5a(5) =15a(6) =34a(7) =69a(8) =121a(9) =205a(10) =314a(11) =479a(12) =679a(13) =961a(14) =1290a(15) =1745a(16) =2239a(17) =2919a(18) =3650a(19) =4599a(20) =5619a(21) =6949a(22) =8290a(23) =10057a(24) =11861a(25) =14105a(26) =16418a(27) =19343a(28) =22165a(29) =25819