Number of 5-tuples of different integers from [ 2,n ] with no global factor.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =6a(6) =21a(7) =56a(8) =125a(9) =251a(10) =456a(11) =786a(12) =1266a(13) =1980a(14) =2946a(15) =4311a(16) =6056a(17) =8436a(18) =11370a(19) =15231a(20) =19866a(21) =25851a(22) =32801a(23) =41655a(24) =51786a(25) =64366a(26) =78601a(27) =96151a(28) =115495a(29) =139246