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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”).

A153691 as a simple table

na(n)
11
21
31
41
52
64
719
821
928
10151
11200
12709
13767
145727
1515908
16162819
17302991

[1,1,1,1,2,4,19,21,28,151,200,709,767,5727,15908,
 162819,302991]