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A221678 as a simple table

n a(n)
1 0
2 2
3 5
4 20
5 68
6 241
7 844
8 2966
9 10413
10 36568
11 128408
12 450913
13 1583400
14 5560186
15 19524853
16 68562444
17 240760252
18 845440977
19 2968805844
20 10425101678
21 36608235997
22 128551546480
23 451414815600
24 1585164405441
25 5566379537040

[0,2,5,20,68,241,844,2966,10413,36568,128408,
 450913,1583400,5560186,19524853,68562444,
 240760252,845440977,2968805844,10425101678,
 36608235997,128551546480,451414815600,
 1585164405441,5566379537040]

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Last modified January 28 12:46 EST 2023. Contains 359892 sequences. (Running on oeis4.)