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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 6 |
| 5 | 95 |
| 6 | 585 |
| 7 | 8974 |
| 8 | 70252 |
| 9 | 1178540 |
| 10 | 10683180 |
| 11 | 201213936 |
| 12 | 2151034776 |
| 13 | 46320457248 |
| 14 | 557515105056 |
| 15 | 12980593545984 |
| 16 | 179077693449600 |
| 17 | 4696518067511040 |
| 18 | 71418673681171200 |
| 19 | 2026061283912560640 |
| 20 | 33687422807179092480 |
| 21 | 1055027603388725452800 |
| 22 | 19337685190135751577600 |
[0,0,1,6,95,585,8974,70252,1178540,10683180, 201213936,2151034776,46320457248,557515105056, 12980593545984,179077693449600,4696518067511040, 71418673681171200,2026061283912560640, 33687422807179092480,1055027603388725452800, 19337685190135751577600] |