A026122 - cp's OEIS frontend

A026122 a(n) is the number of (s(0),s(1),...,s(n)) such that every s(i) is a nonnegative integer, s(0) = 1, s(n) = 1, |s(1) - s(0)| = 1, |s(i) - s(i-1)| <= 1 for i >= 2. Also a(n) = T(n,n), where T is the array in A026120.

n	a(n)
2	2
3	4
4	11
5	28
6	74
7	196
8	525
9	1416
10	3846
11	10508
12	28864
13	79664
14	220818
15	614460
16	1715874
17	4807008
18	13506534
19	38052972
20	107477319
21	304261404
22	863188662
23	2453737132
24	6988033949
25	19935797080
26	56966012730
27	163026450132
28	467219178549
29	1340810339036

[2, 4, 11, 28, 74, 196, 525, 1416, 3846, 10508, 28864, 79664, 220818, 614460, 1715874, 4807008, 13506534, 38052972, 107477319, 304261404, 863188662, 2453737132, 6988033949, 19935797080, 56966012730, 163026450132, 467219178549, 1340810339036]

cp's OEIS Frontend

A026122 a(n) is the number of (s(0),s(1),...,s(n)) such that every s(i) is a nonnegative integer, s(0) = 1, s(n) = 1, |s(1) - s(0)| = 1, |s(i) - s(i-1)| <= 1 for i >= 2. Also a(n) = T(n,n), where T is the array in A026120.

Table of values

List of values