A199894 - cp's OEIS frontend

A199894 Number of -4..4 arrays x(0..n-1) of n elements with zero sum, and adjacent elements not both strictly positive and not both strictly negative.

n	a(n)
1	1
2	9
3	37
4	209
5	1043
6	5725
7	30199
8	164993
9	890299
10	4877477
11	26632013
12	146499083
13	805700567
14	4449304857
15	24590147861
16	136249639279
17	755738351775
18	4199211521573
19	23357174342185
20	130088542750275
21	725223072283995

[1, 9, 37, 209, 1043, 5725, 30199, 164993, 890299, 4877477, 26632013, 146499083, 805700567, 4449304857, 24590147861, 136249639279, 755738351775, 4199211521573, 23357174342185, 130088542750275, 725223072283995]

cp's OEIS Frontend

A199894 Number of -4..4 arrays x(0..n-1) of n elements with zero sum, and adjacent elements not both strictly positive and not both strictly negative.

Table of values

List of values