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.

A032123 Number of 2n-bead black-white reversible strings with n black beads.

Table of values

n a(n)
0 1
1 1
2 4
3 10
4 38
5 126
6 472
7 1716
8 6470
9 24310
10 92504
11 352716
12 1352540
13 5200300
14 20060016
15 77558760
16 300546630
17 1166803110
18 4537591960
19 17672631900
20 68923356788
21 269128937220
22 1052049834576
23 4116715363800
24 16123803193628
25 63205303218876
26 247959271674352
27 973469712824056

List of values

[1, 1, 4, 10, 38, 126, 472, 1716, 6470, 24310, 92504, 352716, 1352540, 5200300, 20060016, 77558760, 300546630, 1166803110, 4537591960, 17672631900, 68923356788, 269128937220, 1052049834576, 4116715363800, 16123803193628, 63205303218876, 247959271674352, 973469712824056]

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

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