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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 44 |
| 5 | 185 |
| 6 | 802 |
| 7 | 3553 |
| 8 | 15994 |
| 9 | 72886 |
| 10 | 335387 |
| 11 | 1555487 |
| 12 | 7261310 |
| 13 | 34083382 |
| 14 | 160730900 |
| 15 | 761039051 |
| 16 | 3616102911 |
| 17 | 17235223345 |
| 18 | 82372594183 |
| 19 | 394648349447 |
| 20 | 1894921311499 |
| 21 | 9116598414141 |
| 22 | 43939539520427 |
| 23 | 212124129983285 |
[1,1,3,11,44,185,802,3553,15994,72886,335387, 1555487,7261310,34083382,160730900,761039051, 3616102911,17235223345,82372594183,394648349447, 1894921311499,9116598414141,43939539520427, 212124129983285] |