A221821 - cp's OEIS frontend

A221821 Number of n X 2 arrays of occupancy after each element stays put or moves to some horizontal or vertical neighbor, without consecutive moves in the same direction.

n	a(n)
1	3
2	31
3	252
4	2113
5	17684
6	147920
7	1237439
8	10351593
9	86594795
10	724396370
11	6059833949
12	50692672540
13	424062286786
14	3547432284249
15	29675536361423
16	248246446379403
17	2076670068892280
18	17372085836189001
19	145323694322280832

[3, 31, 252, 2113, 17684, 147920, 1237439, 10351593, 86594795, 724396370, 6059833949, 50692672540, 424062286786, 3547432284249, 29675536361423, 248246446379403, 2076670068892280, 17372085836189001, 145323694322280832]

cp's OEIS Frontend

A221821 Number of n X 2 arrays of occupancy after each element stays put or moves to some horizontal or vertical neighbor, without consecutive moves in the same direction.

Table of values

List of values