A376756 - OEIS

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A376756

Number of pairs 0 <= x <= y <= n-1 such that x^2 + x*y + y^2 == 0 (mod n).

5

1, 1, 3, 3, 1, 3, 7, 3, 6, 1, 1, 9, 13, 7, 3, 10, 1, 6, 19, 3, 21, 1, 1, 9, 15, 13, 18, 27, 1, 3, 31, 10, 3, 1, 7, 21, 37, 19, 39, 3, 1, 21, 43, 3, 6, 1, 1, 30, 70, 15, 3, 51, 1, 18, 1, 27, 57, 1, 1, 9, 61, 31, 60, 36, 13, 3, 67, 3, 3, 7, 1, 21, 73, 37, 45, 75, 7, 39, 79, 10, 45, 1, 1, 81, 1, 43, 3, 3, 1, 6, 163, 3, 93, 1, 19, 30, 97

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

LINKS

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

PROG

(Python)

def A376756(n):

c = 0

for x in range(n):

z = x**2%n

for y in range(x, n):

if not (z+y*(x+y))%n:

c += 1

return c # Chai Wah Wu, Oct 06 2024

CROSSREFS

Cf. A000086, A046530, A087786, A290731, A376202, A376203, A376755, A376757.

Sequence in context: A332552 A047655 A078685 * A078882 A262220 A325254

Adjacent sequences: A376753 A376754 A376755 * A376757 A376758 A376759

KEYWORD

nonn

AUTHOR

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

STATUS

approved