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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 24 |
| 4 | 111 |
| 5 | 552 |
| 6 | 2873 |
| 7 | 15458 |
| 8 | 85312 |
| 9 | 480314 |
| 10 | 2747845 |
| 11 | 15928080 |
| 12 | 93347153 |
| 13 | 552181372 |
| 14 | 3292571913 |
| 15 | 19769887128 |
| 16 | 119430685503 |
| 17 | 725375643416 |
| 18 | 4426786390959 |
| 19 | 27131644746326 |
| 20 | 166932630227613 |
| 21 | 1030684209393288 |
| 22 | 6383992918008611 |
| 23 | 39657230694169284 |
| 24 | 247008096338698523 |
| 25 | 1542292860296588558 |
| 26 | 9651791500807437834 |
| 27 | 60528789932966226468 |
| 28 | 380333245334293851637 |
| 29 | 2394179659042901060436 |
| 30 | 15096873553004201457425 |
[1,2,6,24,111,552,2873,15458,85312,480314,2747845, 15928080,93347153,552181372,3292571913, 19769887128,119430685503,725375643416, 4426786390959,27131644746326,166932630227613, 1030684209393288,6383992918008611, 39657230694169284,247008096338698523, 1542292860296588558,9651791500807437834, 60528789932966226468,380333245334293851637, 2394179659042901060436,15096873553004201457425] |