A382776 - cp's OEIS frontend

A382776 Triangle read by rows: T(n,k) is the number of ways to place 2n rooks on a (n+k) X (2n-k) board so that there is at least one rook in every column and row and so that each rook is defended by another.

n	a(n)
0	1
1	1
2	1
3	6
4	9
5	6
6	90
7	180
8	180
9	90
10	2520
11	6300
12	8100
13	6300
14	2520
15	113400
16	340200
17	529200
18	529200
19	340200
20	113400
21	7484400
22	26195400
23	47628000
24	57153600
25	47628000
26	26195400
27	7484400
28	681080400
29	2724321600
30	5658206400
31	7858620000
32	7858620000
33	5658206400
34	2724321600
35	681080400

[1, 1, 1, 6, 9, 6, 90, 180, 180, 90, 2520, 6300, 8100, 6300, 2520, 113400, 340200, 529200, 529200, 340200, 113400, 7484400, 26195400, 47628000, 57153600, 47628000, 26195400, 7484400, 681080400, 2724321600, 5658206400, 7858620000, 7858620000, 5658206400, 2724321600, 681080400]

cp's OEIS Frontend

A382776 Triangle read by rows: T(n,k) is the number of ways to place 2n rooks on a (n+k) X (2n-k) board so that there is at least one rook in every column and row and so that each rook is defended by another.

Table of values

List of values

cp's OEIS Frontend

A382776 Triangle read by rows: T(n,k) is the number of ways to place 2*n rooks on a (n+k) X (2*n-k) board so that there is at least one rook in every column and row and so that each rook is defended by another.

Table of values

List of values

A382776 Triangle read by rows: T(n,k) is the number of ways to place 2n rooks on a (n+k) X (2n-k) board so that there is at least one rook in every column and row and so that each rook is defended by another.