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.

A137726 Number of sequences of length n with elements {-2,-1,+1,+2}, counted up to simultaneous reversal and negation, such that the sum of elements of the whole sequence but of no proper subsequence equals 0 modulo n. For n>=4, the number of Hamiltonian (undirected) cycles on the circulant graph C_n(1,2).

Table of values

n a(n)
1 2
2 2
3 8
4 9
5 12
6 16
7 23
8 29
9 41
10 56
11 79
12 110
13 158
14 225
15 325
16 469
17 682
18 991
19 1446
20 2110
21 3085
22 4511
23 6603
24 9666
25 14157
26 20736
27 30380
28 44511
29 65223
30 95575
31 140060
32 205253
33 300800
34 440828
35 646051
36 946817
37 1387613
38 2033628
39 2980411
40 4367986
41 6401578
42 9381949
43 13749897
44 20151433
45 29533342

List of values

[2, 2, 8, 9, 12, 16, 23, 29, 41, 56, 79, 110, 158, 225, 325, 469, 682, 991, 1446, 2110, 3085, 4511, 6603, 9666, 14157, 20736, 30380, 44511, 65223, 95575, 140060, 205253, 300800, 440828, 646051, 946817, 1387613, 2033628, 2980411, 4367986, 6401578, 9381949, 13749897, 20151433, 29533342]

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

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