Quadruples of different integers from [ 1,n ] with no global factor.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =5a(5) =15a(6) =35a(7) =69a(8) =125a(9) =205a(10) =325a(11) =479a(12) =699a(13) =965a(14) =1325a(15) =1745a(16) =2305a(17) =2919a(18) =3735a(19) =4619a(20) =5739a(21) =6949a(22) =8489a(23) =10061a(24) =12081a(25) =14161a(26) =16705a(27) =19343a(28) =22619a(29) =25819