A225307 - cp's OEIS frontend

A225307 Number of nX6 -1,1 arrays such that the sum over i=1..n,j=1..6 of i*x(i,j) is zero and rows are nondecreasing (ways to put 6 thrusters pointing east or west at each of n positions 1..n distance from the hinge of a south-pointing gate without turning the gate).

n	a(n)
1	1
2	3
3	17
4	83
5	427
6	2341
7	13333
8	77721
9	461973
10	2791167
11	17087937
12	105766229
13	660771733
14	4161393187
15	26390549923
16	168386196159
17	1080202503299
18	6962854947491
19	45075011876699
20	292931328936351
21	1910374828122659

[1, 3, 17, 83, 427, 2341, 13333, 77721, 461973, 2791167, 17087937, 105766229, 660771733, 4161393187, 26390549923, 168386196159, 1080202503299, 6962854947491, 45075011876699, 292931328936351, 1910374828122659]

cp's OEIS Frontend

A225307 Number of nX6 -1,1 arrays such that the sum over i=1..n,j=1..6 of i*x(i,j) is zero and rows are nondecreasing (ways to put 6 thrusters pointing east or west at each of n positions 1..n distance from the hinge of a south-pointing gate without turning the gate).

Table of values

List of values