A155919 Number of squared hypotenuses mod n in three dimensions.

1, 2, 3, 4, 5, 6, 7, 7, 9, 10, 11, 12, 13, 14, 15, 14, 17, 18, 19, 20, 21, 22, 23, 21, 25, 26, 27, 28, 29, 30, 31, 27, 33, 34, 35, 36, 37, 38, 39, 35, 41, 42, 43, 44, 45, 46, 47, 42, 49, 50, 51, 52, 53, 54, 55, 49, 57, 58, 59, 60, 61, 62, 63, 54, 65, 66, 67, 68, 69, 70, 71, 63

Offset

1,2

Comments

Number of images of the map (x,y,z) -> x^2+y^2+z^2 in Z_n.

Links

Table of n, a(n) for n=1..72.

Mathematica

(For[v = Table[0, {m, 1, n^3}]; m = 1; i = 0, i < n, i++, For[j = 0, j < n, j++, For[k = 0, k < n, k++, v[[m]] = Mod[i^2 + j^2 + k^2, n]; m = m + 1]]]; Length[Union[v]])

Crossrefs

Sequence in context: A017862 A265539 A254926 * A265540 A075011 A283001

Adjacent sequences: A155916 A155917 A155918 * A155920 A155921 A155922

Keyword

mult,nonn

Author

Steven Finch, Jan 30 2009

Status

approved