A269907 - OEIS

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A269907 as a simple table

n	a(n)
0	1
1	4
2	44
3	220
4	956
5	3964
6	16124
7	65020
8	261116
9	1046524
10	4190204
11	16769020
12	67092476
13	268402684
14	1073676284
15	4294836220

[1,4,44,220,956,3964,16124,65020,261116,1046524, 4190204,16769020,67092476,268402684,1073676284, 4294836220]