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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 5 |
| 2 | 16 |
| 3 | 78 |
| 4 | 470 |
| 5 | 3153 |
| 6 | 22588 |
| 7 | 169188 |
| 8 | 1308762 |
| 9 | 10374460 |
| 10 | 83829856 |
| 11 | 687929086 |
| 12 | 5717602930 |
| 13 | 48030047206 |
| 14 | 407142435000 |
| 15 | 3478286028840 |
| 16 | 29917720938690 |
| 17 | 258866494630164 |
| 18 | 2251694583485824 |
| 19 | 19677972159742360 |
| 20 | 172694287830500440 |
| 21 | 1521328368800877065 |
[0,5,16,78,470,3153,22588,169188,1308762,10374460, 83829856,687929086,5717602930,48030047206, 407142435000,3478286028840,29917720938690, 258866494630164,2251694583485824, 19677972159742360,172694287830500440, 1521328368800877065] |