A225311 - cp's OEIS frontend

A225311 Number of 4 X n -1,1 arrays such that the sum over i=1..4,j=1..n of i*x(i,j) is zero and rows are nondecreasing (ways to put n thrusters pointing east or west at each of 4 positions 1..n distance from the hinge of a south-pointing gate without turning the gate).

n	a(n)
1	2
2	7
3	16
4	31
5	52
6	83
7	122
8	175
9	238
10	317
11	410
12	523
13	650
14	801
15	970
16	1165
17	1380
18	1625
19	1892
20	2193
21	2518
22	2879
23	3268
24	3697
25	4154
26	4655
27	5188
28	5767
29	6380
30	7043
31	7742
32	8495
33	9286
34	10133
35	11022
36	11971
37	12962
38	14017
39	15118
40	16285
41	17500
42	18785
43	20120
44	21529
45	22990

[2, 7, 16, 31, 52, 83, 122, 175, 238, 317, 410, 523, 650, 801, 970, 1165, 1380, 1625, 1892, 2193, 2518, 2879, 3268, 3697, 4154, 4655, 5188, 5767, 6380, 7043, 7742, 8495, 9286, 10133, 11022, 11971, 12962, 14017, 15118, 16285, 17500, 18785, 20120, 21529, 22990]

cp's OEIS Frontend

A225311 Number of 4 X n -1,1 arrays such that the sum over i=1..4,j=1..n of i*x(i,j) is zero and rows are nondecreasing (ways to put n thrusters pointing east or west at each of 4 positions 1..n distance from the hinge of a south-pointing gate without turning the gate).

Table of values

List of values