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A002293 as a simple table

n a(n)
0 1
1 1
2 4
3 22
4 140
5 969
6 7084
7 53820
8 420732
9 3362260
10 27343888
11 225568798
12 1882933364
13 15875338990
14 134993766600
15 1156393243320
16 9969937491420
17 86445222719724
18 753310723010608
19 6594154339031800
20 57956002331347120
21 511238042454541545

[1,1,4,22,140,969,7084,53820,420732,3362260,
 27343888,225568798,1882933364,15875338990,
 134993766600,1156393243320,9969937491420,
 86445222719724,753310723010608,6594154339031800,
 57956002331347120,511238042454541545]

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Last modified December 10 05:49 EST 2018. Contains 318044 sequences. (Running on oeis4.)