A220563 - cp's OEIS frontend

A220563 Number of ways to reciprocally link elements of an 2 X n array either to themselves or to exactly one horizontal or antidiagonal neighbor.

n	a(n)
1	1
2	5
3	14
4	47
5	149
6	481
7	1544
8	4965
9	15957
10	51293
11	164870
12	529947
13	1703417
14	5475329
15	17599456
16	56570281
17	181834969
18	584475733
19	1878691886
20	6038716423
21	19410365421
22	62391120801
23	200545011400
24	644615789581
25	2072001259341
26	6660074556205

[1, 5, 14, 47, 149, 481, 1544, 4965, 15957, 51293, 164870, 529947, 1703417, 5475329, 17599456, 56570281, 181834969, 584475733, 1878691886, 6038716423, 19410365421, 62391120801, 200545011400, 644615789581, 2072001259341, 6660074556205]

cp's OEIS Frontend

A220563 Number of ways to reciprocally link elements of an 2 X n array either to themselves or to exactly one horizontal or antidiagonal neighbor.

Table of values

List of values