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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.

A387361 Number of 2n-step walks from (0, 0) to (0, 0) on square lattice with winding number zero around (1/2, 1/2).

Table of values

n a(n)
0 1
1 4
2 34
3 360
4 4240
5 53184
6 695462
7 9366968
8 128974482
9 1806466376
10 25649169360
11 368251171264
12 5336142742044
13 77928806182640
14 1145686661461166
15 16941028325651416
16 251769181131306246
17 3758317957588392856
18 56324288926707167928
19 847084621934648027872
20 12780033173479276354696

List of values

[1, 4, 34, 360, 4240, 53184, 695462, 9366968, 128974482, 1806466376, 25649169360, 368251171264, 5336142742044, 77928806182640, 1145686661461166, 16941028325651416, 251769181131306246, 3758317957588392856, 56324288926707167928, 847084621934648027872, 12780033173479276354696]

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

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