a(n) = Sum_[k unrelated to n and k<n] a(k) = Sum_[k < n such that GCD(k,n) != 1 and k does not divide n ] a(k); a(1) = a(2) = a(3) = a(4) = 1.
A118657
a(n) = Sum_[k unrelated to n and k<n] a(k) = Sum_[k < n such that GCD(k,n) != 1 and k does not divide n ] a(k); a(1) = a(2) = a(3) = a(4) = 1.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =0a(5) =1a(6) =0a(7) =1a(8) =1a(9) =3a(10) =0a(11) =5a(12) =0a(13) =11a(14) =10a(15) =20a(16) =0a(17) =51a(18) =0a(19) =99a(20) =79a(21) =192a(22) =0a(23) =466a(24) =112a(25) =850a(26) =612a(27) =1767a(28) =0a(29) =4267
External references
- oeis: A118657