A396175 Consider the square spiral with its cells numbered starting at 0. Seven 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, 9, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, 8, 0, 0, 5, 0, 16, 15, 0, 6, 0, 10, 0, 17, 7, 24, 0, 0, 0, 0, 22, 23, 12, 0, 29, 13, 14, 0, 0, 19, 20, 30, 0, 18, 0, 21, 0, 28, 0, 25, 31, 26, 0, 35, 38, 0, 37, 32, 44, 0, 0, 0, 0, 0, 27, 0, 34, 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(A396167(k)) = 7*k - 6.

a(A396168(k)) = 7*k - 5.

a(A396169(k)) = 7*k - 4.

a(A396170(k)) = 7*k - 3.

a(A396171(k)) = 7*k - 2.

a(A396172(k)) = 7*k - 1.

a(A396173(k)) = 7*k.

a(A396174(k)) = 0.

Prog

(PARI) \\ See Links section.

Crossrefs

Cf. A392177, A395364, A396167, A396168, A396169, A396170, A396171, A396172, A396173, A396174.

Sequence in context: A258194 A033554 A091930 * A124526 A124418 A175177

Adjacent sequences: A396172 A396173 A396174 * A396176 A396177 A396178

Keyword

nonn

Author

Rémy Sigrist, May 23 2026

Status

approved