A284418 - cp's OEIS frontend

A284418 Number of self-avoiding planar walks of length n*(n+1)/2 starting at (0,0), ending at (n,0), remaining in the first quadrant and using steps (0,1), (1,0), (1,1), (-1,1), and (1,-1) with the restriction that (0,1) is never used below the diagonal and (1,0) is never used above the diagonal.

n	a(n)
0	1
1	1
2	1
3	7
4	10
5	31
6	69
7	196
8	451
9	1168
10	2813
11	7119
12	17618
13	44206
14	111399
15	277972
16	709411
17	1763795
18	4543873
19	11269489
20	29244239
21	72402587
22	188977618
23	467258134
24	1225383748
25	3026799348
26	7969173506
27	19669004793
28	51959167749
29	128161003199
30	339530403506

[1, 1, 1, 7, 10, 31, 69, 196, 451, 1168, 2813, 7119, 17618, 44206, 111399, 277972, 709411, 1763795, 4543873, 11269489, 29244239, 72402587, 188977618, 467258134, 1225383748, 3026799348, 7969173506, 19669004793, 51959167749, 128161003199, 339530403506]

cp's OEIS Frontend

A284418 Number of self-avoiding planar walks of length n*(n+1)/2 starting at (0,0), ending at (n,0), remaining in the first quadrant and using steps (0,1), (1,0), (1,1), (-1,1), and (1,-1) with the restriction that (0,1) is never used below the diagonal and (1,0) is never used above the diagonal.

Table of values

List of values