A215871 - cp's OEIS frontend

A215871 Number of permutations of 0..floor((3*n-2)/2) on odd squares of an 3Xn array such that each row, column, diagonal and (downwards) antidiagonal of odd squares is increasing.

n	a(n)
1	1
2	1
3	1
4	2
5	4
6	12
7	29
8	110
9	290
10	1274
11	3532
12	17136
13	49100
14	255816
15	750325
16	4124406
17	12310294
18	70549050
19	213446666
20	1264752060
21	3868253164
22	23555382240
23	72686739116
24	452806924752

[1, 1, 1, 2, 4, 12, 29, 110, 290, 1274, 3532, 17136, 49100, 255816, 750325, 4124406, 12310294, 70549050, 213446666, 1264752060, 3868253164, 23555382240, 72686739116, 452806924752]

cp's OEIS Frontend

A215871 Number of permutations of 0..floor((3*n-2)/2) on odd squares of an 3Xn array such that each row, column, diagonal and (downwards) antidiagonal of odd squares is increasing.

Table of values

List of values