A022732 - OEIS

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A022732 as a simple table

n	a(n)
0	1
1	8
2	52
3	272
4	1274
5	5408
6	21448
7	80080
8	285043
9	972496
10	3200644
11	10199456
12	31592350
13	95366176
14	281269560
15	812094448
16	2299480441
17	6394796832
18	17489643664
19	47096042032
20	124993380566
21	327249781952

[1,8,52,272,1274,5408,21448,80080,285043,972496, 3200644,10199456,31592350,95366176,281269560, 812094448,2299480441,6394796832,17489643664, 47096042032,124993380566,327249781952]