A026110 - cp's OEIS frontend

A026110 a(n) = number of (s(0), s(1), ..., s(n)) such that every s(i) is a nonnegative integer, s(0) = 0, s(1) = 1, s(n) = 4, |s(i) - s(i-1)| <= 1 for i >= 2. Also a(n) = T(n,n-4), where T is the array defined in A026105.

n	a(n)
4	1
5	4
6	15
7	50
8	160
9	496
10	1509
11	4530
12	13475
13	39820
14	117117
15	343278
16	1003665
17	2929200
18	8537910
19	24863724
20	72363951
21	210532540
22	612398025
23	1781252110
24	5181318054
25	15073505216
26	43860668800
27	127657036000
28	371654416575
29	1082359229796

[1, 4, 15, 50, 160, 496, 1509, 4530, 13475, 39820, 117117, 343278, 1003665, 2929200, 8537910, 24863724, 72363951, 210532540, 612398025, 1781252110, 5181318054, 15073505216, 43860668800, 127657036000, 371654416575, 1082359229796]

cp's OEIS Frontend

A026110 a(n) = number of (s(0), s(1), ..., s(n)) such that every s(i) is a nonnegative integer, s(0) = 0, s(1) = 1, s(n) = 4, |s(i) - s(i-1)| <= 1 for i >= 2. Also a(n) = T(n,n-4), where T is the array defined in A026105.

Table of values

List of values