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.

A328688 Number of double palindrome structures of length n using exactly two different symbols.

Table of values

n a(n)
1 0
2 1
3 3
4 7
5 15
6 25
7 49
8 79
9 129
10 211
11 341
12 517
13 819
14 1275
15 1863
16 2959
17 4335
18 6703
19 9709
20 15067
21 21367
22 33419
23 47081
24 72949
25 102315
26 158887
27 220881
28 342615
29 475107
30 734815
31 1015777
32 1569679
33 2161943
34 3337951
35 4587199
36 7069747
37 9699291
38 14932443
39 20445519
40 31441339

List of values

[0, 1, 3, 7, 15, 25, 49, 79, 129, 211, 341, 517, 819, 1275, 1863, 2959, 4335, 6703, 9709, 15067, 21367, 33419, 47081, 72949, 102315, 158887, 220881, 342615, 475107, 734815, 1015777, 1569679, 2161943, 3337951, 4587199, 7069747, 9699291, 14932443, 20445519, 31441339]