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| n | a(n) |
|---|---|
| 1 | 48 |
| 2 | 238 |
| 3 | 990 |
| 4 | 3764 |
| 5 | 13830 |
| 6 | 49722 |
| 7 | 176928 |
| 8 | 629352 |
| 9 | 2235852 |
| 10 | 8002034 |
| 11 | 28683258 |
| 12 | 103771062 |
| 13 | 376062560 |
| 14 | 1374796560 |
| 15 | 5031081278 |
| 16 | 18549468152 |
| 17 | 68412809246 |
| 18 | 253875030476 |
| 19 | 941922579066 |
| 20 | 3512298224194 |
| 21 | 13090258692986 |
| 22 | 48987088758646 |
[48,238,990,3764,13830,49722,176928,629352, 2235852,8002034,28683258,103771062,376062560, 1374796560,5031081278,18549468152,68412809246, 253875030476,941922579066,3512298224194, 13090258692986,48987088758646] |