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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 9 |
| 3 | 33 |
| 4 | 145 |
| 5 | 624 |
| 6 | 2811 |
| 7 | 12770 |
| 8 | 59045 |
| 9 | 274746 |
| 10 | 1291347 |
| 11 | 6099917 |
| 12 | 28987799 |
| 13 | 138336728 |
| 14 | 662762769 |
| 15 | 3185314137 |
| 16 | 15353072483 |
| 17 | 74180403680 |
| 18 | 359207508273 |
| 19 | 1742771595073 |
| 20 | 8470077478449 |
| 21 | 41229298992010 |
| 22 | 200969968948619 |
| 23 | 980856465445634 |
| 24 | 4792716506836087 |
| 25 | 23443124281677520 |
| 26 | 114780479390363687 |
[1,2,9,33,145,624,2811,12770,59045,274746,1291347, 6099917,28987799,138336728,662762769,3185314137, 15353072483,74180403680,359207508273, 1742771595073,8470077478449,41229298992010, 200969968948619,980856465445634,4792716506836087, 23443124281677520,114780479390363687] |