A076363 a(n) = A000010(n) - A061498(n).

1, 1, 1, 1, 3, 1, 5, 3, 4, 2, 9, 2, 11, 4, 5, 7, 15, 4, 17, 6, 9, 8, 21, 6, 18, 10, 16, 10, 27, 5, 29, 15, 17, 14, 21, 10, 35, 16, 21, 14, 39, 9, 41, 18, 21, 20, 45, 14, 40, 18, 29, 22, 51, 16, 37, 22, 33, 26, 57, 13, 59, 28, 33, 31, 45, 17, 65, 30, 41, 21, 69, 22, 71, 34, 37, 34

Offset: 1

Author

Labos Elemer, Oct 09 2002

Keywords

• nonn

Crossrefs

Cf. A000010, A061498.

Programs

PARI

a061498(n) = {my(va = select(x->(gcd(n, x)==1), [1..n])); vd = vector(#va-1, k, va[k+1] - va[k]); #Set(vd);}
a(n) = eulerphi(n) - a061498(n); \\ Michel Marcus, Jul 08 2018