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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 13 |
| 5 | 106 |
| 6 | 694 |
| 7 | 3991 |
| 8 | 21067 |
| 9 | 104680 |
| 10 | 497452 |
| 11 | 2285053 |
| 12 | 10222777 |
| 13 | 44788342 |
| 14 | 192970834 |
| 15 | 820244467 |
| 16 | 3448381783 |
| 17 | 14367483412 |
| 18 | 59421385000 |
| 19 | 244271688313 |
| 20 | 999169721125 |
| 21 | 4070288777410 |
| 22 | 16525230017710 |
| 23 | 66906367267471 |
| 24 | 270271938430243 |
[0,0,0,1,13,106,694,3991,21067,104680,497452, 2285053,10222777,44788342,192970834,820244467, 3448381783,14367483412,59421385000,244271688313, 999169721125,4070288777410,16525230017710, 66906367267471,270271938430243] |