a(n) is number of k for which C(n,k) is not divisible by n.

Terms

a(0) =1a(1) =0a(2) =2a(3) =2a(4) =3a(5) =2a(6) =5a(7) =2a(8) =5a(9) =4a(10) =5a(11) =2a(12) =8a(13) =2a(14) =9a(15) =8a(16) =9a(17) =2a(18) =9a(19) =2a(20) =11a(21) =8a(22) =9a(23) =2a(24) =15a(25) =6a(26) =9a(27) =10a(28) =15a(29) =2