A018997 - 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

A018997 as a simple table

n	a(n)
2	2
3	7
4	36
5	230
6	1104
7	6657
8	38976
9	247431
10	1617560
11	10806202
12	73706144
13	510591393
14	3568689922
15	25130781435
16	178056349424

[2,7,36,230,1104,6657,38976,247431,1617560, 10806202,73706144,510591393,3568689922, 25130781435,178056349424]