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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 3 |
| 3 | 6 |
| 4 | 38 |
| 5 | 160 |
| 6 | 905 |
| 7 | 4830 |
| 8 | 28308 |
| 9 | 166992 |
| 10 | 1024758 |
| 11 | 6389460 |
| 12 | 40724244 |
| 13 | 263385408 |
| 14 | 1728855843 |
| 15 | 11484066594 |
| 16 | 77129083947 |
| 17 | 522959361936 |
| 18 | 3576364370022 |
| 19 | 24643554967656 |
| 20 | 170964572526549 |
| 21 | 1193217941096604 |
| 22 | 8372537679729462 |
| 23 | 59027518046416656 |
| 24 | 417904230297222132 |
[1,0,3,6,38,160,905,4830,28308,166992,1024758, 6389460,40724244,263385408,1728855843,11484066594, 77129083947,522959361936,3576364370022, 24643554967656,170964572526549,1193217941096604, 8372537679729462,59027518046416656, 417904230297222132] |