A177409 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

A177409 as a simple table

n	a(n)
1	1
2	2
3	12
4	108
5	1208
6	15536
7	220832
8	3390480
9	55411872
10	954553664
11	17211258240
12	323148560768
13	6293245904640
14	126740607526400
15	2633207863038976
16	56330595706808576
17	1238815010325576192
18	27970477203200824320

[1,2,12,108,1208,15536,220832,3390480,55411872, 954553664,17211258240,323148560768,6293245904640, 126740607526400,2633207863038976, 56330595706808576,1238815010325576192, 27970477203200824320]