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Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 9 |
| 4 | 30 |
| 5 | 90 |
| 6 | 286 |
| 7 | 941 |
| 8 | 3072 |
| 9 | 10308 |
| 10 | 34814 |
| 11 | 118138 |
| 12 | 406368 |
| 13 | 1399630 |
| 14 | 4858636 |
| 15 | 16948153 |
| 16 | 59302432 |
| 17 | 208587930 |
| 18 | 735602234 |
| 19 | 2602943312 |
| 20 | 9239044912 |
| 21 | 32867768218 |
| 22 | 117244508016 |
| 23 | 419105764722 |
| 24 | 1501220073148 |
| 25 | 5388115272948 |
| 26 | 19371438711296 |
| 27 | 69764776854918 |
| 28 | 251641664047600 |
| 29 | 908984140277160 |
| 30 | 3288068461179108 |
[1,1,4,9,30,90,286,941,3072,10308,34814,118138, 406368,1399630,4858636,16948153,59302432, 208587930,735602234,2602943312,9239044912, 32867768218,117244508016,419105764722, 1501220073148,5388115272948,19371438711296, 69764776854918,251641664047600,908984140277160, 3288068461179108] |