A348060 a(n) = Sum_{k=1..n, gcd(n,k) = 1} (k-1) / gcd(n,k-1).

0, 0, 1, 1, 6, 2, 15, 5, 15, 8, 45, 7, 66, 18, 30, 21, 120, 18, 153, 23, 70, 50, 231, 24, 190, 72, 147, 56, 378, 40, 435, 85, 194, 128, 280, 55, 630, 162, 284, 87, 780, 68, 861, 153, 264, 242, 1035, 91, 861, 200, 502, 213, 1326, 156, 788, 205, 642, 392, 1653, 110, 1770, 450, 606, 341, 1136

Offset

1,5

Links

Table of n, a(n) for n=1..65.

Mathematica

Table[Sum[If[GCD[n, k] == 1, (k - 1)/GCD[n, k - 1], 0], {k, n}], {n, 65}]

Prog

(PARI) a(n) = sum(k=1, n, if (gcd(n, k)==1, (k-1)/gcd(n, k-1))); \\ Michel Marcus, Sep 27 2021

Crossrefs

Cf. A057661, A062355, A348061.

Sequence in context: A095951 A116420 A069268 * A082155 A128225 A136398

Adjacent sequences: A348057 A348058 A348059 * A348061 A348062 A348063

Keyword

nonn

Author

Ilya Gutkovskiy, Sep 26 2021

Status

approved