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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”).

A280767 as a simple table

na(n)
11
21
34
416
570
6322
71556
839698
9207217

[1,1,4,16,70,322,1556,39698,207217]