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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 11 |
| 3 | 46 |
| 4 | 209 |
| 5 | 1003 |
| 6 | 5002 |
| 7 | 25665 |
| 8 | 134605 |
| 9 | 718371 |
| 10 | 3888633 |
| 11 | 21298962 |
| 12 | 117823660 |
| 13 | 657344600 |
| 14 | 3694378463 |
| 15 | 20896495211 |
| 16 | 118865999117 |
| 17 | 679545095167 |
| 18 | 3902327585407 |
| 19 | 22499738052954 |
| 20 | 130200110475407 |
| 21 | 755927955655813 |
| 22 | 4402088019958400 |
| 23 | 25706104810367515 |
[1,3,11,46,209,1003,5002,25665,134605,718371, 3888633,21298962,117823660,657344600,3694378463, 20896495211,118865999117,679545095167, 3902327585407,22499738052954,130200110475407, 755927955655813,4402088019958400, 25706104810367515] |