A333046 a(1) = 1; a(n) = n * Sum_{d|n, d < n, gcd(d, n/d) = 1} a(d) / d.

1, 2, 3, 4, 5, 18, 7, 8, 9, 30, 11, 36, 13, 42, 45, 16, 17, 54, 19, 60, 63, 66, 23, 72, 25, 78, 27, 84, 29, 390, 31, 32, 99, 102, 105, 108, 37, 114, 117, 120, 41, 546, 43, 132, 135, 138, 47, 144, 49, 150, 153, 156, 53, 162, 165, 168, 171, 174, 59, 780, 61, 186, 189, 64, 195

Offset: 1

Author

Ilya Gutkovskiy, Mar 06 2020

Keywords

• nonn

Crossrefs

Cf. A000961 (fixed points), A050369, A325446.

Programs

Mathematica

a[1] = 1; a[n_] := a[n] = n Sum[If[GCD[d, n/d] == 1 && d < n, a[d]/d, 0], {d, Divisors[n]}]; Table[a[n], {n, 1, 65}]