A390736 - OEIS

%I #17 Nov 24 2025 19:33:24

%S 1,0,0,0,0,0,0,0,0,0,0,20,263928,22868187338,1034937133971366,

%T 46636257344451763934,1990740376914748532578610,

%U 84433188888432939678771427334,3657103798685771128160178096325444,165258835167767029550384983801808942466

%N Number of n X n grids with 3 non-attacking kings on each row.

%H Hamidreza Maleki Tirabadi, <a href="/A390736/b390736.txt">Table of n, a(n) for n = 0..30</a>

%F See A390419.

%e a(11) = 20. One of the 20 solutions is:

%e   Row 1:  [0, 2, 4]  -> * ° * ° * ° ° ° ° ° °

%e   Row 2:  [6, 8, 10] -> ° ° ° ° ° ° * ° * ° *

%e   Row 3:  [0, 2, 4]  -> * ° * ° * ° ° ° ° ° °

%e   Row 4:  [6, 8, 10] -> ° ° ° ° ° ° * ° * ° *

%e   Row 5:  [0, 2, 4]  -> * ° * ° * ° ° ° ° ° °

%e   Row 6:  [6, 8, 10] -> ° ° ° ° ° ° * ° * ° *

%e   Row 7:  [0, 2, 4]  -> * ° * ° * ° ° ° ° ° °

%e   Row 8:  [6, 8, 10] -> ° ° ° ° ° ° * ° * ° *

%e   Row 9:  [0, 2, 4]  -> * ° * ° * ° ° ° ° ° °

%e   Row 10: [6, 8, 10] -> ° ° ° ° ° ° * ° * ° *

%e   Row 11: [0, 2, 4]  -> * ° * ° * ° ° ° ° ° °

%Y Column k=3 of A390419.

%Y Cf. A389770, A387098.

%K nonn

%O 0,12

%A _Hamidreza Maleki Tirabadi_, Nov 16 2025