Number of (unordered) triples of integers from [1,n] with no common factors between pairs.

Terms

a(0) =0a(1) =0a(2) =1a(3) =2a(4) =7a(5) =8a(6) =19a(7) =25a(8) =37a(9) =42a(10) =73a(11) =79a(12) =124a(13) =138a(14) =159a(15) =183a(16) =262a(17) =277a(18) =378a(19) =405a(20) =454a(21) =491a(22) =640a(23) =668a(24) =794a(25) =850a(26) =959a(27) =1016a(28) =1257a(29) =1285