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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 2 |
| 3 | 2 |
| 4 | 14 |
| 5 | 42 |
| 6 | 222 |
| 7 | 1066 |
| 8 | 6078 |
| 9 | 36490 |
| 10 | 238046 |
| 11 | 1653610 |
| 12 | 12214270 |
| 13 | 95361866 |
| 14 | 784071966 |
| 15 | 6764984362 |
| 16 | 61066919230 |
| 17 | 575200190986 |
| 18 | 5640081557598 |
| 19 | 57450510336234 |
| 20 | 606773139773054 |
| 21 | 6633515763375306 |
| 22 | 74950634205257630 |
| 23 | 873995513192234410 |
| 24 | 10504736507220958142 |
| 25 | 129983468625156713354 |
[1,0,2,2,14,42,222,1066,6078,36490,238046,1653610, 12214270,95361866,784071966,6764984362, 61066919230,575200190986,5640081557598, 57450510336234,606773139773054,6633515763375306, 74950634205257630,873995513192234410, 10504736507220958142,129983468625156713354] |