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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 16 |
| 3 | 56 |
| 4 | 296 |
| 5 | 1052 |
| 6 | 4952 |
| 7 | 17292 |
| 8 | 70512 |
| 9 | 249712 |
| 10 | 931226 |
| 11 | 3212690 |
| 12 | 11399590 |
| 13 | 38331770 |
| 14 | 130310820 |
| 15 | 428389292 |
| 16 | 1408697596 |
| 17 | 4524980036 |
| 18 | 14486512316 |
| 19 | 45558807176 |
| 20 | 142488702483 |
| 21 | 439559056419 |
| 22 | 1347096766984 |
| 23 | 4082169772704 |
| 24 | 12286806024269 |
| 25 | 36629267989081 |
[1,1,16,56,296,1052,4952,17292,70512,249712, 931226,3212690,11399590,38331770,130310820, 428389292,1408697596,4524980036,14486512316, 45558807176,142488702483,439559056419, 1347096766984,4082169772704,12286806024269, 36629267989081] |