Number of 5-tuples of different integers from [ 1,n ] with no global factor.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =6a(6) =21a(7) =56a(8) =126a(9) =251a(10) =461a(11) =786a(12) =1281a(13) =1981a(14) =2981a(15) =4311a(16) =6131a(17) =8436a(18) =11496a(19) =15246a(20) =20076a(21) =25851a(22) =33166a(23) =41656a(24) =52281a(25) =64436a(26) =79316a(27) =96151a(28) =116626a(29) =139246