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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 5 |
| 3 | 25 |
| 4 | 141 |
| 5 | 911 |
| 6 | 6703 |
| 7 | 55581 |
| 8 | 513929 |
| 9 | 5248891 |
| 10 | 58724211 |
| 11 | 714554633 |
| 12 | 9397715341 |
| 13 | 132870076119 |
| 14 | 2009977939271 |
| 15 | 32396622193141 |
| 16 | 554297204755473 |
| 17 | 10034223725151731 |
| 18 | 191617109450287579 |
| 19 | 3849745645109036001 |
[0,1,5,25,141,911,6703,55581,513929,5248891, 58724211,714554633,9397715341,132870076119, 2009977939271,32396622193141,554297204755473, 10034223725151731,191617109450287579, 3849745645109036001] |