Quadruples of different integers from [ 2,n ] with no common factors between triples.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =3a(5) =12a(6) =22a(7) =48a(8) =75a(9) =148a(10) =194a(11) =335a(12) =443a(13) =630a(14) =804a(15) =1192a(16) =1401a(17) =1977a(18) =2345a(19) =2980a(20) =3525a(21) =4651a(22) =5222a(23) =6612a(24) =7588a(25) =9117a(26) =10314a(27) =12781a(28) =13879a(29) =16945