A128532 - OEIS

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A128532 as a simple table

n	a(n)
1	1
2	1
3	1
4	2
5	3
6	5
7	18
8	325
9	1512
10	14365
11	349272
12	21734245
13	276623424
14	6933892901
15	577589709312
16	492757099009565
17	16532350249637376
18	1086038875887212525
19	1240124656925798848512
20	1450308695702968720107785

[1,1,1,2,3,5,18,325,1512,14365,349272,21734245, 276623424,6933892901,577589709312,492757099009565, 16532350249637376,1086038875887212525, 1240124656925798848512,1450308695702968720107785]