A003274 - cp's OEIS frontend

A003274 Number of key permutations of length n: permutations {a_i} with |a_i - a_{i-1}| = 1 or 2.

n	a(n)
0	1
1	1
2	2
3	6
4	12
5	20
6	34
7	56
8	88
9	136
10	208
11	314
12	470
13	700
14	1038
15	1534
16	2262
17	3330
18	4896
19	7192
20	10558
21	15492
22	22724
23	33324
24	48860
25	71630
26	105002
27	153912
28	225594
29	330650
30	484618
31	710270
32	1040980
33	1525660
34	2235994
35	3277040
36	4802768
37	7038832
38	10315944
39	15118786

[1, 1, 2, 6, 12, 20, 34, 56, 88, 136, 208, 314, 470, 700, 1038, 1534, 2262, 3330, 4896, 7192, 10558, 15492, 22724, 33324, 48860, 71630, 105002, 153912, 225594, 330650, 484618, 710270, 1040980, 1525660, 2235994, 3277040, 4802768, 7038832, 10315944, 15118786]

cp's OEIS Frontend

A003274 Number of key permutations of length n: permutations {a_i} with |a_i - a_{i-1}| = 1 or 2.

Table of values

List of values