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

Terms

a(0) =0a(1) =0a(2) =1a(3) =4a(4) =9a(5) =19a(6) =31a(7) =51a(8) =73a(9) =109a(10) =141a(11) =196a(12) =247a(13) =318a(14) =388a(15) =493a(16) =576a(17) =712a(18) =826a(19) =981a(20) =1126a(21) =1336a(22) =1494a(23) =1741a(24) =1951a(25) =2223a(26) =2467a(27) =2818a(28) =3066a(29) =3472