A191563 - cp's OEIS frontend

A191563 For n >= 3, draw a regular n-sided polygon and its n(n-3)/2 diagonals, so there are n(n-1)/2 lines; a(n) is the number of ways to choose a subset of these lines (subsets differing by a rotation or reflection are regarded as identical). a(1)=1, a(2)=2 by convention.

n	a(n)
1	1
2	2
3	4
4	19
5	136
6	3036
7	151848
8	16814116
9	3818273456
10	1759237059488
11	1637673128642016
12	3074457382841680224
13	11624286729262765320064
14	88424288520685885682129216
15	1352160640243480723729126645248
16	41538374868278630828076760060403776
17	2562126056816477844908944991509312669696

[1, 2, 4, 19, 136, 3036, 151848, 16814116, 3818273456, 1759237059488, 1637673128642016, 3074457382841680224, 11624286729262765320064, 88424288520685885682129216, 1352160640243480723729126645248, 41538374868278630828076760060403776, 2562126056816477844908944991509312669696]

cp's OEIS Frontend

A191563 For n >= 3, draw a regular n-sided polygon and its n(n-3)/2 diagonals, so there are n(n-1)/2 lines; a(n) is the number of ways to choose a subset of these lines (subsets differing by a rotation or reflection are regarded as identical). a(1)=1, a(2)=2 by convention.

Table of values

List of values