A242534 - cp's OEIS frontend

A242534 Number of cyclic arrangements of S={1,2,...,n} such that the difference of any two neighbors is not coprime to their sum.

n	a(n)
1	1
2	0
3	0
4	0
5	0
6	0
7	0
8	0
9	0
10	72
11	288
12	3600
13	17856
14	174528
15	2540160
16	14768640
17	101030400
18	1458266112
19	11316188160
20	140951577600
21	2659218508800
22	30255151463424
23	287496736542720
24	5064092578713600
25	76356431941939200
26	987682437203558400
27	19323690313219522560

[1, 0, 0, 0, 0, 0, 0, 0, 0, 72, 288, 3600, 17856, 174528, 2540160, 14768640, 101030400, 1458266112, 11316188160, 140951577600, 2659218508800, 30255151463424, 287496736542720, 5064092578713600, 76356431941939200, 987682437203558400, 19323690313219522560]

cp's OEIS Frontend

A242534 Number of cyclic arrangements of S={1,2,...,n} such that the difference of any two neighbors is not coprime to their sum.

Table of values

List of values