A061709 - cp's OEIS frontend

A061709 Consider a (hollow) triangle with n cells on each edge, for a total of 3(n-1) cells if n>1, or 1 cell if n=1; a(n) is number of ways of labeling cells with 0's and 1's; triangle may be rotated and turned over.

n	a(n)
1	1
2	4
3	20
4	104
5	752
6	5600
7	44224
8	350592
9	2800384
10	22377984
11	178990080
12	1431721984
13	11453509632
14	91626496000
15	733009854464
16	5864066220032
17	46912512917504
18	375300002545664
19	3002399885885440
20	24019198281252864
21	192153585175232512
22	1537228674957312000

[1, 4, 20, 104, 752, 5600, 44224, 350592, 2800384, 22377984, 178990080, 1431721984, 11453509632, 91626496000, 733009854464, 5864066220032, 46912512917504, 375300002545664, 3002399885885440, 24019198281252864, 192153585175232512, 1537228674957312000]

cp's OEIS Frontend

A061709 Consider a (hollow) triangle with n cells on each edge, for a total of 3(n-1) cells if n>1, or 1 cell if n=1; a(n) is number of ways of labeling cells with 0's and 1's; triangle may be rotated and turned over.

Table of values

List of values