A225344 - cp's OEIS frontend

A225344 Number of nX8 -1,1 arrays such that the sum over i=1..n,j=1..8 of i*x(i,j) is zero, the sum of x(i,j) is zero, and rows are nondecreasing (number of ways to distribute 8-across galley oarsmen left-right at n fore-aft positions so that there are no turning moments on the ship).

n	a(n)
1	1
2	1
3	5
4	27
5	171
6	1081
7	7261
8	50659
9	364051
10	2676331
11	20044255
12	152452967
13	1174757541
14	9154016699
15	72023900129
16	571498084391
17	4568690484153
18	36765944370729
19	297627015600415
20	2422216988266317
21	19808260648181603

[1, 1, 5, 27, 171, 1081, 7261, 50659, 364051, 2676331, 20044255, 152452967, 1174757541, 9154016699, 72023900129, 571498084391, 4568690484153, 36765944370729, 297627015600415, 2422216988266317, 19808260648181603]

cp's OEIS Frontend

A225344 Number of nX8 -1,1 arrays such that the sum over i=1..n,j=1..8 of i*x(i,j) is zero, the sum of x(i,j) is zero, and rows are nondecreasing (number of ways to distribute 8-across galley oarsmen left-right at n fore-aft positions so that there are no turning moments on the ship).

Table of values

List of values