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A181344 as a simple table

na(n)
10
20
31
41
55
625
7161
81112
98787
1076156
11728699
127609065
1386162795
141050755884
1513728407061
16191309852944

[0,0,1,1,5,25,161,1112,8787,76156,728699,7609065,
 86162795,1050755884,13728407061,191309852944]