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A027881 as a simple table

na(n)
11
21
32
44
59
620
751
8121
9321
10826
112186
125789
1316114
1442449
15118281
16328425
17908933
182510553
197138324
2019869748

[1,1,2,4,9,20,51,121,321,826,2186,5789,16114,
 42449,118281,328425,908933,2510553,7138324,
 19869748]