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.

A135473 a(n) = number of strings of length n that can be obtained by starting with abc and repeatedly doubling any substring in place.

Table of values

n a(n)
1 0
2 0
3 1
4 3
5 8
6 21
7 54
8 138
9 355
10 924
11 2432
12 6461
13 17301
14 46657
15 126656
16 345972
17 950611
18 2626253
19 7292268
20 20342805
21 56993909
22 160317859
23 452642235
24 1282466920
25 3645564511
26 10395117584
27 29727982740
28 85251828792
29 245120276345
30 706529708510
31 2041260301955
32 5910531770835
33 17149854645474
34 49859456251401
35 145223624492108
36 423722038708874
37 1238318400527185

List of values

[0, 0, 1, 3, 8, 21, 54, 138, 355, 924, 2432, 6461, 17301, 46657, 126656, 345972, 950611, 2626253, 7292268, 20342805, 56993909, 160317859, 452642235, 1282466920, 3645564511, 10395117584, 29727982740, 85251828792, 245120276345, 706529708510, 2041260301955, 5910531770835, 17149854645474, 49859456251401, 145223624492108, 423722038708874, 1238318400527185]

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

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