A283303 List points (x,y) having integer coordinates with x >= y >= 0, sorted first by x^2+y^2 and in case of a tie, by x-coordinate. Sequence gives x-coordinates.

0, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 3, 4, 4, 5, 5, 5, 4, 5, 6, 6, 6, 5, 6, 7, 5, 7, 6, 7, 7, 6, 8, 7, 8, 8, 6, 8, 7, 8, 9, 9, 7, 9, 8, 9, 9, 7, 8, 10, 10, 10, 9, 10, 8, 10, 9, 11, 11, 10, 11, 8, 9, 11, 10, 11, 12, 9, 12, 11, 12, 10, 12, 11, 12, 9, 10, 12, 13, 11, 13, 13, 13, 12, 10, 11, 13, 12, 13, 14

Offset

1,4

Links

Hugo Pfoertner, Table of n, a(n) for n = 1..10000

Example

The first few points (listing [x^2+y^2,x,y]) are:
[0, 0, 0], [1, 1, 0], [2, 1, 1], [4, 2, 0], [5, 2, 1], [8, 2, 2], [9, 3, 0], [10, 3, 1], [13, 3, 2], [16, 4, 0], [17, 4, 1], [18, 3, 3], [20, 4, 2], [25, 4, 3], [25, 5, 0], [26, 5, 1], [29, 5, 2], [32, 4, 4], [34, 5, 3], [36, 6, 0], [37, 6, 1], [40, 6, 2], [41, 5, 4], [45, 6, 3], [49, 7, 0], ...

Maple

L:=[];
M:=30;
for i from 0 to M do
for j from 0 to i do
L:=[op(L), [i^2+j^2, i, j]]; od: od:
t3:= sort(L, proc(a, b) evalb(a[1]<=b[1]); end);
t3x:=[seq(t3[i][2], i=1..100)]; # A283303
t3y:=[seq(t3[i][3], i=1..100)]; # A283304

Mathematica

nt = 105; (* number of terms to produce *)
S[m_] := S[m] = Table[{x, y}, {y, 0, m}, {x, y, m}] // Flatten[#, 1]& // SortBy[#, {#.#&, #[[1]]&}]& // #[[All, 1]]& // PadRight[#, nt]&
S[m = 2];
S[m = 2 m];
While[S[m] =!= S[m/2], m = 2 m];
S[m] (* Jean-François Alcover, Mar 05 2023 *)

Crossrefs

For the y coordinates see A283304.

See also A283305-A283308.

Sequence in context: A165360 A340542 A351167 * A280079 A116513 A122651

Adjacent sequences: A283300 A283301 A283302 * A283304 A283305 A283306

Keyword

nonn

Author

N. J. A. Sloane, Mar 04 2017, following a suggestion from Ahmet Arduç.

Status

approved