A396331 Consider the square spiral with its cells numbered starting at 0. Three players, Red, Green and Blue, take turns and place knights at the smallest unoccupied cell not attacked by an opposing knight, where Red is only opposed by Blue, Green by Red and Blue by Green. Sequence lists squares occupied by a Green knight.

1, 4, 7, 14, 20, 22, 24, 26, 31, 35, 46, 47, 49, 50, 52, 56, 61, 65, 67, 69, 71, 75, 80, 81, 83, 94, 99, 100, 105, 114, 117, 119, 121, 125, 131, 133, 135, 137, 140, 144, 146, 148, 150, 152, 160, 162, 168, 172, 179, 181, 182, 184, 186, 189, 195, 226, 232, 234

Offset

1,2

Comments

See A396330.

Links

Michael S. Branicky, Table of n, a(n) for n = 1..10000

Michael S. Branicky, Python program for OEIS A396330, A396331 and A396332

Nick J. Nauta, The first 1000 cells of the spiral

Nick J. Nauta, The first 10000 cells of the spiral

Nick J. Nauta, The first 100000 cells of the spiral

Nick J. Nauta, The first 1000000 cells of the spiral

Prog

(Python) # See Links section.

Crossrefs

Cf. A392177, A395646, A396330, A396332.

Sequence in context: A161426 A115759 A157615 * A338551 A188319 A171378

Adjacent sequences: A396328 A396329 A396330 * A396332 A396333 A396334

Keyword

nonn

Author

Nick J. Nauta, May 22 2026

Status

approved