A228956 - cp's OEIS frontend

A228956 Number of undirected circular permutations i_0, i_1, ..., i_n of 0, 1, ..., n such that all the 2*n+2 numbers |i_0 +/- i_1|, |i_1 +/- i_2|, ..., |i_{n-1} +/- i_n|, |i_n +/- i_0| have the form (p-1)/2 with p an odd prime.

n	a(n)
1	1
2	1
3	1
4	1
5	5
6	9
7	17
8	84
9	30
10	127
11	791
12	2404
13	11454
14	27680
15	25942
16	137272
17	515947
18	2834056
19	26583034
20	82099932
21	306004652
22	4518630225
23	11242369312
24	8942966426
25	95473633156
26	533328765065

[1, 1, 1, 1, 5, 9, 17, 84, 30, 127, 791, 2404, 11454, 27680, 25942, 137272, 515947, 2834056, 26583034, 82099932, 306004652, 4518630225, 11242369312, 8942966426, 95473633156, 533328765065]

cp's OEIS Frontend

A228956 Number of undirected circular permutations i_0, i_1, ..., i_n of 0, 1, ..., n such that all the 2*n+2 numbers |i_0 +/- i_1|, |i_1 +/- i_2|, ..., |i_{n-1} +/- i_n|, |i_n +/- i_0| have the form (p-1)/2 with p an odd prime.

Table of values

List of values