A396166 Consider the square spiral with its cells numbered starting at 0. Six players take turns and place knights at the smallest unoccupied cell not attacked by an existing knight of a different player; a(n) = k if the n-th cell has been occupied at the k-th turn, a(n) = 0 otherwise.

1, 2, 3, 4, 8, 0, 0, 0, 0, 0, 0, 7, 0, 0, 0, 0, 10, 0, 0, 0, 5, 13, 14, 0, 0, 6, 0, 9, 20, 15, 19, 0, 0, 0, 16, 0, 11, 0, 12, 0, 25, 17, 31, 0, 23, 29, 0, 26, 18, 21, 0, 0, 0, 37, 0, 32, 27, 22, 0, 0, 24, 0, 28, 0, 30, 0, 33, 0, 35, 0, 34, 0, 41, 0, 0, 0, 0, 0

Offset

0,2

Links

Rémy Sigrist, Table of n, a(n) for n = 0..10000

Rémy Sigrist, PARI program

Formula

a(A396129(k)) = 6*k - 5.

a(A396130(k)) = 6*k - 4.

a(A396131(k)) = 6*k - 3.

a(A396132(k)) = 6*k - 2.

a(A396133(k)) = 6*k - 1.

a(A396134(k)) = 6*k.

a(A396135(k)) = 0.

Prog

(PARI) \\ See Links section.

Crossrefs

Cf. A392177, A395364, A396129, A396130, A396131, A396132, A396133, A396134, A396135.

Sequence in context: A328322 A109617 A181881 * A229597 A366656 A175060

Adjacent sequences: A396163 A396164 A396165 * A396167 A396168 A396169

Keyword

nonn

Author

Rémy Sigrist, May 22 2026

Status

approved