A205979 - OEIS

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A205979 as a simple table

n	a(n)
1	81
2	423
3	2232
4	11568
5	60432
6	315357
7	1643538
8	8574615
9	44720319
10	233223303
11	1216434498
12	6344254641
13	33088388283
14	172573776357
15	900058321935
16	4694264219421
17	24482997863997
18	127691295254772
19	665975373377820

[81,423,2232,11568,60432,315357,1643538,8574615, 44720319,233223303,1216434498,6344254641, 33088388283,172573776357,900058321935, 4694264219421,24482997863997,127691295254772, 665975373377820]