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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 3 |
| 5 | 13 |
| 6 | 65 |
| 7 | 397 |
| 8 | 2819 |
| 9 | 22831 |
| 10 | 207605 |
| 11 | 2094121 |
| 12 | 23205383 |
| 13 | 280224451 |
| 14 | 3662810249 |
| 15 | 51523391965 |
| 16 | 776082247979 |
| 17 | 12463259986087 |
| 18 | 212573743211549 |
| 19 | 3837628837381201 |
| 20 | 73108996989052175 |
| 21 | 1465703611456618891 |
| 22 | 30847249002794047793 |
| 23 | 679998362512214208901 |
| 24 | 15668677914172813691699 |
| 25 | 376683592679293811722735 |
[0,0,1,3,13,65,397,2819,22831,207605,2094121, 23205383,280224451,3662810249,51523391965, 776082247979,12463259986087,212573743211549, 3837628837381201,73108996989052175, 1465703611456618891,30847249002794047793, 679998362512214208901,15668677914172813691699, 376683592679293811722735] |