A217694 - cp's OEIS frontend

A217694 Number of n-variations of the set {1,2,...,n+1} satisfying p(i)-i in {-2,0,2}, i=1..n (an n-variation of the set N_{n+s} = {1,2,...,n+s} is any 1-to-1 mapping p from the set N_n = {1,2,...,n} into N_{n+s} = {1,2,...,n+s}).

n	a(n)
0	1
1	1
2	2
3	4
4	8
5	12
6	21
7	35
8	60
9	96
10	160
11	260
12	429
13	693
14	1134
15	1836
16	2992
17	4840
18	7865
19	12727
20	20648
21	33408
22	54144
23	87608
24	141897
25	229593
26	371722
27	601460
28	973560
29	1575252
30	2549421
31	4125051
32	6675460
33	10801120
34	17478176
35	28280284
36	45761045
37	74042925
38	119808150

[1, 1, 2, 4, 8, 12, 21, 35, 60, 96, 160, 260, 429, 693, 1134, 1836, 2992, 4840, 7865, 12727, 20648, 33408, 54144, 87608, 141897, 229593, 371722, 601460, 973560, 1575252, 2549421, 4125051, 6675460, 10801120, 17478176, 28280284, 45761045, 74042925, 119808150]

cp's OEIS Frontend

A217694 Number of n-variations of the set {1,2,...,n+1} satisfying p(i)-i in {-2,0,2}, i=1..n (an n-variation of the set N_{n+s} = {1,2,...,n+s} is any 1-to-1 mapping p from the set N_n = {1,2,...,n} into N_{n+s} = {1,2,...,n+s}).

Table of values

List of values