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Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A146809 as a simple table

na(n)
11
21
31
41
51
61
71
81
917
1017
1165
1265
13349
14349
153731
163731
1777219
1877219
192029815
202029815
2163522619
2263522619

[1,1,1,1,1,1,1,1,17,17,65,65,349,349,3731,3731,
 77219,77219,2029815,2029815,63522619,63522619]