login

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”).

A242530 as a simple table

na(n)
10
20
31
40
52
68
70
80
9224
10754
110
1226256
130
140
1522472304
160
1790654576
18277251016
190
207852128780

[0,0,1,0,2,8,0,0,224,754,0,26256,0,0,22472304,0,
 90654576,277251016,0,7852128780]