Number of 5-tuples of different integers from [ 2,n ] with no common factors among quadruples.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =6a(6) =18a(7) =52a(8) =105a(9) =226a(10) =374a(11) =688a(12) =1047a(13) =1690a(14) =2406a(15) =3696a(16) =4901a(17) =7140a(18) =9291a(19) =12688a(20) =16091a(21) =21710a(22) =26434a(23) =34648a(24) =42081a(25) =53026a(26) =63410a(27) =79828a(28) =92681a(29) =114846