A333388 Number of solutions to x^y == -1 (mod n) where 0 <= x < n and 1 <= y <= n.

1, 2, 2, 2, 5, 3, 6, 4, 9, 11, 10, 6, 21, 11, 8, 8, 33, 15, 22, 10, 19, 19, 22, 12, 45, 43, 36, 24, 53, 15, 46, 16, 29, 67, 30, 30, 85, 43, 34, 20, 109, 35, 66, 38, 39, 43, 46, 24, 77, 95, 26, 44, 101, 63, 52, 46, 67, 107, 58, 30, 181, 91, 120, 32, 159, 61, 106

Offset

1,2

Links

Table of n, a(n) for n=1..67.

Example

a(4) = 2, because there are 2 solutions to x^y == -1 (mod 4): 3^1 == -1 (4), 3^3 == -1 (4).

Prog

(PARI) for(n=1, 67, print1(sum(x=0, n-1, sum(y=1, n, Mod(x, n)^y==n-1)), ", ")) \\ Hugo Pfoertner, Mar 22 2020

Crossrefs

Cf. A333386, A333387.

Sequence in context: A210239 A115253 A154429 * A174577 A194684 A076737

Adjacent sequences: A333385 A333386 A333387 * A333389 A333390 A333391

Keyword

nonn

Author

Franz Vrabec, Mar 18 2020

Extensions

More terms from Hugo Pfoertner, Mar 22 2020

Status

approved