A199893 - cp's OEIS frontend

A199893 Number of -3..3 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	7
3	25
4	111
5	461
6	2035
7	8823
8	39053
9	172355
10	767425
11	3420017
12	15311495
13	68665323
14	308805403
15	1391091909
16	6278869703
17	28381760049
18	128482271031
19	582346682067
20	2642616002605
21	12004291295381
22	54583533395613
23	248409301882015

[1, 7, 25, 111, 461, 2035, 8823, 39053, 172355, 767425, 3420017, 15311495, 68665323, 308805403, 1391091909, 6278869703, 28381760049, 128482271031, 582346682067, 2642616002605, 12004291295381, 54583533395613, 248409301882015]

cp's OEIS Frontend

A199893 Number of -3..3 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