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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 7 |
| 3 | 31 |
| 4 | 264 |
| 5 | 1856 |
| 6 | 12703 |
| 7 | 71457 |
| 8 | 348622 |
| 9 | 1477513 |
| 10 | 5584477 |
| 11 | 19071063 |
| 12 | 59748789 |
| 13 | 173510124 |
| 14 | 471615249 |
| 15 | 1208756261 |
| 16 | 2940705168 |
| 17 | 6827326093 |
| 18 | 15197942364 |
| 19 | 32566376769 |
| 20 | 67408927586 |
| 21 | 135184087822 |
| 22 | 263356043520 |
| 23 | 499542801451 |
| 24 | 924501767285 |
| 25 | 1672391804486 |
[1,1,7,31,264,1856,12703,71457,348622,1477513, 5584477,19071063,59748789,173510124,471615249, 1208756261,2940705168,6827326093,15197942364, 32566376769,67408927586,135184087822,263356043520, 499542801451,924501767285,1672391804486] |