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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 10 |
| 4 | 37 |
| 5 | 121 |
| 6 | 406 |
| 7 | 1324 |
| 8 | 3865 |
| 9 | 9937 |
| 10 | 22816 |
| 11 | 47686 |
| 12 | 92269 |
| 13 | 167545 |
| 14 | 288562 |
| 15 | 475336 |
| 16 | 753841 |
| 17 | 1157089 |
| 18 | 1726300 |
| 19 | 2512162 |
| 20 | 3576181 |
| 21 | 4992121 |
| 22 | 6847534 |
| 23 | 9245380 |
| 24 | 12305737 |
| 25 | 16167601 |
| 26 | 20990776 |
| 27 | 26957854 |
| 28 | 34276285 |
| 29 | 43180537 |
| 30 | 53934346 |
| 31 | 66833056 |
| 32 | 82206049 |
| 33 | 100419265 |
[1,1,4,10,37,121,406,1324,3865,9937,22816,47686, 92269,167545,288562,475336,753841,1157089,1726300, 2512162,3576181,4992121,6847534,9245380,12305737, 16167601,20990776,26957854,34276285,43180537, 53934346,66833056,82206049,100419265] |