A396975 Follow along the squares in the Hilbert curve. Place a chess king at each square that is not attacked by an existing king. This sequence gives the squares occupied by the kings.

0, 4, 8, 14, 16, 20, 24, 30, 32, 36, 40, 46, 49, 54, 58, 60, 64, 70, 74, 76, 82, 85, 89, 92, 97, 101, 104, 111, 113, 119, 123, 127, 130, 133, 137, 140, 146, 149, 153, 156, 161, 165, 168, 175, 177, 183, 187, 191, 194, 197, 201, 204, 210, 214, 218, 220, 225, 230

Offset

1,2

Links

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Rémy Sigrist, Representation of the first terms (the color is function of x mod 2, y mod 2)

Rémy Sigrist, PARI program

Example

The Hilbert curve begins:
     .---.  49---.---.   .---.---.
         |   |       |   |       |
    60---.   .---.  46---.  40---.
     |           |           |
     .   .---.   .   .---.   .---.
     |   |   |   |   |   |       |
    58---.  54---.  32   .--36---.
                     |
     .---.   .---.   .   .---.---.
     |   |   |   |   |   |       |
     4   .---8   .  30---.  24---.
     |           |           |
     .---.   .---.   .---.   .---.
         |   |       |   |       |
     0---.  14---.--16   .--20---.

Prog

(PARI) \\ See Links section.

Crossrefs

Cf. A059252, A059253, A307188, A397052.

Sequence in context: A381630 A312245 A312246 * A312247 A138634 A312248

Adjacent sequences: A396971 A396972 A396973 * A396976 A396977 A396978

Keyword

nonn

Author

Rémy Sigrist, Jun 12 2026

Status

approved