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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 5 |
| 2 | 25 |
| 3 | 215 |
| 4 | 2425 |
| 5 | 33875 |
| 6 | 569125 |
| 7 | 11160035 |
| 8 | 250047025 |
| 9 | 6302723075 |
| 10 | 176522216125 |
| 11 | 5438291613155 |
| 12 | 182773714292425 |
| 13 | 6654680279353475 |
| 14 | 260930805319957525 |
| 15 | 10961922511422743075 |
| 16 | 491220886240696086625 |
| 17 | 23388149451193115459075 |
| 18 | 1179066988050425638569325 |
[1,5,25,215,2425,33875,569125,11160035,250047025, 6302723075,176522216125,5438291613155, 182773714292425,6654680279353475, 260930805319957525,10961922511422743075, 491220886240696086625,23388149451193115459075, 1179066988050425638569325] |