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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 10 |
| 5 | 35 |
| 6 | 128 |
| 7 | 483 |
| 8 | 1866 |
| 9 | 7344 |
| 10 | 29342 |
| 11 | 118701 |
| 12 | 485249 |
| 13 | 2001467 |
| 14 | 8319019 |
| 15 | 34810084 |
| 16 | 146519286 |
| 17 | 619939204 |
| 18 | 2635257950 |
| 19 | 11248889770 |
| 20 | 48198305528 |
| 21 | 207222648334 |
| 22 | 893704746508 |
| 23 | 3865335575201 |
| 24 | 16761606193951 |
| 25 | 72860178774410 |
| 26 | 317418310631983 |
| 27 | 1385703968792040 |
[1,0,1,3,10,35,128,483,1866,7344,29342,118701, 485249,2001467,8319019,34810084,146519286, 619939204,2635257950,11248889770,48198305528, 207222648334,893704746508,3865335575201, 16761606193951,72860178774410,317418310631983, 1385703968792040] |