A026027 - cp's OEIS frontend

A026027 a(n) = number of (s(0), s(1), ..., s(2n-1)) such that s(i) is a nonnegative integer and |s(i) - s(i-1)| = 1 for i = 1,2,...,n, s(0) = 3, s(2n-1) = 6. Also a(n) = T(2n-1,n-2), where T is defined in A026022.

n	a(n)
2	1
3	5
4	21
5	84
6	329
7	1274
8	4900
9	18768
10	71706
11	273581
12	1043119
13	3976700
14	15163785
15	57848910
16	220830360
17	843621600
18	3225477150
19	12342901410
20	47274639594
21	181230395304
22	695384769002
23	2670587146260
24	10265249568536
25	39491671919840

[1, 5, 21, 84, 329, 1274, 4900, 18768, 71706, 273581, 1043119, 3976700, 15163785, 57848910, 220830360, 843621600, 3225477150, 12342901410, 47274639594, 181230395304, 695384769002, 2670587146260, 10265249568536, 39491671919840]

cp's OEIS Frontend

A026027 a(n) = number of (s(0), s(1), ..., s(2n-1)) such that s(i) is a nonnegative integer and |s(i) - s(i-1)| = 1 for i = 1,2,...,n, s(0) = 3, s(2n-1) = 6. Also a(n) = T(2n-1,n-2), where T is defined in A026022.

Table of values

List of values