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A002457 as a simple table

n a(n)
0 1
1 6
2 30
3 140
4 630
5 2772
6 12012
7 51480
8 218790
9 923780
10 3879876
11 16224936
12 67603900
13 280816200
14 1163381400
15 4808643120
16 19835652870
17 81676217700
18 335780006100
19 1378465288200
20 5651707681620
21 23145088600920
22 94684453367400
23 386971244197200
24 1580132580471900

[1,6,30,140,630,2772,12012,51480,218790,923780,
 3879876,16224936,67603900,280816200,1163381400,
 4808643120,19835652870,81676217700,335780006100,
 1378465288200,5651707681620,23145088600920,
 94684453367400,386971244197200,1580132580471900]

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Last modified May 3 08:32 EDT 2024. Contains 372207 sequences. (Running on oeis4.)