A396175 - OEIS

%I #5 May 23 2026 10:44:14

%S 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,

%T 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,

%U 26,0,35,38,0,37,32,44,0,0,0,0,0,27,0,34,0,0,0,0,0

%N 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.

%H Rémy Sigrist, <a href="/A396175/b396175.txt">Table of n, a(n) for n = 0..10000</a>

%H Rémy Sigrist, <a href="/A396175/a396175.gp.txt">PARI program</a>

%F a(A396167(k)) = 7*k - 6.

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

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

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

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

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

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

%F a(A396174(k)) = 0.

%o (PARI) \\ See Links section.

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

%K nonn

%O 0,2

%A _Rémy Sigrist_, May 23 2026