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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 3 |
| 4 | 50 |
| 5 | 472 |
| 6 | 3253 |
| 7 | 18435 |
| 8 | 91028 |
| 9 | 404154 |
| 10 | 1646000 |
| 11 | 6232542 |
| 12 | 22151853 |
| 13 | 74433912 |
| 14 | 237790084 |
| 15 | 725557353 |
| 16 | 2122652633 |
| 17 | 5973816190 |
| 18 | 16219720273 |
| 19 | 42595011951 |
| 20 | 108438121237 |
| 21 | 268160583493 |
| 22 | 645345542877 |
| 23 | 1513887056435 |
[0,0,3,50,472,3253,18435,91028,404154,1646000, 6232542,22151853,74433912,237790084,725557353, 2122652633,5973816190,16219720273,42595011951, 108438121237,268160583493,645345542877, 1513887056435] |