A026015 - cp's OEIS frontend

A026015 a(n) = number of (s(0), s(1), ..., s(2n)) such that s(i) is a nonnegative integer and |s(i) - s(i-1)| = 1 for i = 1,2,...,n, s(0) = 2, s(2n) = 8. Also a(n) = T(2n,n-3), where T is the array defined in A026009.

n	a(n)
3	1
4	8
5	45
6	219
7	987
8	4248
9	17748
10	72675
11	293436
12	1172908
13	4653935
14	18366075
15	72186075
16	282861360
17	1105877880
18	4316224860
19	16825024134
20	65525448960
21	255024693434
22	992116674142
23	3858537980286
24	15004402265424
25	58343871881400

[1, 8, 45, 219, 987, 4248, 17748, 72675, 293436, 1172908, 4653935, 18366075, 72186075, 282861360, 1105877880, 4316224860, 16825024134, 65525448960, 255024693434, 992116674142, 3858537980286, 15004402265424, 58343871881400]

cp's OEIS Frontend

A026015 a(n) = number of (s(0), s(1), ..., s(2n)) such that s(i) is a nonnegative integer and |s(i) - s(i-1)| = 1 for i = 1,2,...,n, s(0) = 2, s(2n) = 8. Also a(n) = T(2n,n-3), where T is the array defined in A026009.

Table of values

List of values