A121688 - 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

A121688 as a simple table

n	a(n)
0	1
1	2
2	3
3	6
4	15
5	49
6	210
7	1191
8	8981
9	90405
10	1219297
11	22105506
12	540476679
13	17875316557
14	802011318369
15	48947781204529
16	4073596070782653
17	463360670014324153
18	72183972733773232361
19	15430254274957714069057

[1,2,3,6,15,49,210,1191,8981,90405,1219297, 22105506,540476679,17875316557,802011318369, 48947781204529,4073596070782653, 463360670014324153,72183972733773232361, 15430254274957714069057]