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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.

A056510 Number of periodic palindromic structures of length n using exactly four different symbols.

Table of values

n a(n)
1 0
2 0
3 0
4 0
5 0
6 1
7 1
8 7
9 10
10 43
11 65
12 220
13 350
14 1059
15 1701
16 4803
17 7770
18 21105
19 34105
20 90248
21 145750
22 379391
23 611501
24 1573432
25 2532530
26 6465473
27 10391745
28 26379908
29 42355950
30 107091559
31 171798901
32 433093459
33 694337290
34 1746630985
35 2798806985
36 7029341790
37 11259666950

List of values

[0, 0, 0, 0, 0, 1, 1, 7, 10, 43, 65, 220, 350, 1059, 1701, 4803, 7770, 21105, 34105, 90248, 145750, 379391, 611501, 1573432, 2532530, 6465473, 10391745, 26379908, 42355950, 107091559, 171798901, 433093459, 694337290, 1746630985, 2798806985, 7029341790, 11259666950]

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

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