A376757 Number of pairs 0 <= x <= y <= n-1 such that x^3 == y^3 (mod n).

1, 2, 3, 5, 5, 6, 13, 14, 18, 10, 11, 15, 25, 26, 15, 28, 17, 36, 37, 25, 39, 22, 23, 42, 35, 50, 81, 71, 29, 30, 61, 72, 33, 34, 65, 99, 73, 74, 75, 70, 41, 78, 85, 55, 90, 46, 47, 84, 112, 70, 51, 137, 53, 162, 55, 218, 111, 58, 59, 75, 121, 122, 288, 208, 125, 66, 133, 85, 69, 130, 71, 306, 145, 146, 105, 203, 143, 150, 157

Offset

1,2

Comments

A087786 includes pairs (x,y) with x>y (which are excluded from the present sequence).

Links

Seiichi Manyama, Table of n, a(n) for n = 1..10000

Prog

(PARI) a(n) = sum(x=0, n-1, sum(y=x, n-1, Mod(x, n)^3 == Mod(y, n)^3)); \\ Michel Marcus, Oct 06 2024
(Python)
from collections import Counter
def A376757(n): return sum(d*(d+1)>>1 for d in Counter(pow(x, 3, n) for x in range(n)).values()) # Chai Wah Wu, Oct 06 2024

Crossrefs

Cf. A000086, A087786, A046530, A290731, A376202, A376203, A376755, A376756.

Sequence in context: A163831 A326399 A192419 * A081836 A263721 A351259

Adjacent sequences: A376754 A376755 A376756 * A376758 A376759 A376760

Keyword

nonn

Author

Tom Duff and N. J. A. Sloane, Oct 06 2024

Status

approved