A026023 - cp's OEIS frontend

A026023 a(n) = number of (s(0), s(1), ..., s(n)) such that s(i) is a nonnegative integer and |s(i) - s(i-1)| = 1 for i = 1,2,...,n and s(0) = 3. Also a(n) = Sum{T(n,k), k = 0,1,...,[ (n+3)/2 ]}, where T is defined in A026022.

n	a(n)
0	1
1	2
2	4
3	8
4	15
5	30
6	56
7	112
8	210
9	420
10	792
11	1584
12	3003
13	6006
14	11440
15	22880
16	43758
17	87516
18	167960
19	335920
20	646646
21	1293292
22	2496144
23	4992288
24	9657700
25	19315400
26	37442160
27	74884320
28	145422675
29	290845350
30	565722720
31	1131445440
32	2203961430
33	4407922860

[1, 2, 4, 8, 15, 30, 56, 112, 210, 420, 792, 1584, 3003, 6006, 11440, 22880, 43758, 87516, 167960, 335920, 646646, 1293292, 2496144, 4992288, 9657700, 19315400, 37442160, 74884320, 145422675, 290845350, 565722720, 1131445440, 2203961430, 4407922860]

cp's OEIS Frontend

A026023 a(n) = number of (s(0), s(1), ..., s(n)) such that s(i) is a nonnegative integer and |s(i) - s(i-1)| = 1 for i = 1,2,...,n and s(0) = 3. Also a(n) = Sum{T(n,k), k = 0,1,...,[ (n+3)/2 ]}, where T is defined in A026022.

Table of values

List of values