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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.

A032091 Number of reversible strings with n-1 beads of 2 colors. 4 beads are black. String is not palindromic.

Table of values

n a(n)
6 2
7 6
8 16
9 32
10 60
11 100
12 160
13 240
14 350
15 490
16 672
17 896
18 1176
19 1512
20 1920
21 2400
22 2970
23 3630
24 4400
25 5280
26 6292
27 7436
28 8736
29 10192
30 11830
31 13650
32 15680
33 17920
34 20400
35 23120
36 26112
37 29376
38 32946
39 36822
40 41040
41 45600
42 50540
43 55860
44 61600
45 67760
46 74382
47 81466
48 89056

List of values

[2, 6, 16, 32, 60, 100, 160, 240, 350, 490, 672, 896, 1176, 1512, 1920, 2400, 2970, 3630, 4400, 5280, 6292, 7436, 8736, 10192, 11830, 13650, 15680, 17920, 20400, 23120, 26112, 29376, 32946, 36822, 41040, 45600, 50540, 55860, 61600, 67760, 74382, 81466, 89056]

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

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