A025180 - cp's OEIS frontend

A025180 a(n) = number of (s(0), s(1), ..., s(n)) such that s(i) is an integer, s(0) = 0, |s(1)| = 1, |s(i) - s(i-1)| <= 1 for i >= 2, s(n) = 2. Also a(n) = T(n,n-2), where T is the array defined in A025177.

n	a(n)
2	1
3	2
4	7
5	20
6	60
7	176
8	518
9	1520
10	4461
11	13090
12	38423
13	112828
14	331487
15	974442
16	2866125
17	8434992
18	24838275
19	73181142
20	215729781
21	636275820
22	1877569134
23	5543095404
24	16372140876
25	48377825216
26	143009973875
27	422918975726
28	1251154692297

[1, 2, 7, 20, 60, 176, 518, 1520, 4461, 13090, 38423, 112828, 331487, 974442, 2866125, 8434992, 24838275, 73181142, 215729781, 636275820, 1877569134, 5543095404, 16372140876, 48377825216, 143009973875, 422918975726, 1251154692297]

cp's OEIS Frontend

A025180 a(n) = number of (s(0), s(1), ..., s(n)) such that s(i) is an integer, s(0) = 0, |s(1)| = 1, |s(i) - s(i-1)| <= 1 for i >= 2, s(n) = 2. Also a(n) = T(n,n-2), where T is the array defined in A025177.

Table of values

List of values