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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 12 |
| 4 | 57 |
| 5 | 318 |
| 6 | 2190 |
| 7 | 20298 |
| 8 | 265557 |
| 9 | 4683954 |
| 10 | 102511182 |
| 11 | 2622117720 |
| 12 | 75857421522 |
| 13 | 2436766744728 |
| 14 | 85885843375992 |
| 15 | 3292322691248310 |
| 16 | 136306472824555725 |
| 17 | 6059583761048830290 |
| 18 | 287832499902612461910 |
| 19 | 14546503423112218184280 |
| 20 | 779260996651844076919230 |
| 21 | 44104811071523533909346100 |
| 22 | 2629647430438623322437523380 |
| 23 | 164732335319839237173383723220 |
[1,1,3,12,57,318,2190,20298,265557,4683954, 102511182,2622117720,75857421522,2436766744728, 85885843375992,3292322691248310, 136306472824555725,6059583761048830290, 287832499902612461910,14546503423112218184280, 779260996651844076919230, 44104811071523533909346100, 2629647430438623322437523380, 164732335319839237173383723220] |