cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A260155 Number of walks of length 2n on the square lattice that start and end at (0,0) and avoid the negative quadrant.

Table of values

n a(n)
0 1
1 4
2 32
3 318
4 3530
5 41944
6 522010
7 6719018
8 88726840
9 1195527822
10 16373466714
11 227280520316
12 3190715296368
13 45226324937400
14 646392346047930
15 9305481272839662
16 134815491199174476
17 1964195875748858812
18 28761433275110249932
19 423052415434610432816

List of values

[1, 4, 32, 318, 3530, 41944, 522010, 6719018, 88726840, 1195527822, 16373466714, 227280520316, 3190715296368, 45226324937400, 646392346047930, 9305481272839662, 134815491199174476, 1964195875748858812, 28761433275110249932, 423052415434610432816]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.