A361295 - cp's OEIS frontend

A361295 A variant of payphone permutations: given a row of n payphones, a(n) is the number ways for n people to choose the payphones in order, where each person chooses an unoccupied payphone such that the closest occupied payphone is as distant as possible, and among the available payphones adjacent to a single occupied payphone the most preferred are payphones at open ends.

n	a(n)
1	1
2	2
3	4
4	6
5	12
6	40
7	144
8	384
9	1008
10	6816
11	33600
12	115200
13	783360
14	3024000
15	16450560
16	140636160
17	558351360
18	2262435840
19	29599395840
20	180278784000
21	2124328550400
22	13664957644800
23	127667338444800
24	852837440716800
25	11377123378790400
26	116737211695104000
27	816490952589312000

[1, 2, 4, 6, 12, 40, 144, 384, 1008, 6816, 33600, 115200, 783360, 3024000, 16450560, 140636160, 558351360, 2262435840, 29599395840, 180278784000, 2124328550400, 13664957644800, 127667338444800, 852837440716800, 11377123378790400, 116737211695104000, 816490952589312000]

cp's OEIS Frontend

Table of values

List of values