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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 11 |
| 4 | 44 |
| 5 | 163 |
| 6 | 665 |
| 7 | 2746 |
| 8 | 11685 |
| 9 | 50560 |
| 10 | 222560 |
| 11 | 990647 |
| 12 | 4461545 |
| 13 | 20261605 |
| 14 | 92750052 |
| 15 | 427391693 |
| 16 | 1980932854 |
| 17 | 9228373502 |
| 18 | 43188083319 |
| 19 | 202928074526 |
| 20 | 956967526605 |
| 21 | 4527549376056 |
| 22 | 21483545535985 |
| 23 | 102213596708559 |
| 24 | 487492635095972 |
| 25 | 2330199032630362 |
| 26 | 11161042429983908 |
| 27 | 53558921980348752 |
[1,1,4,11,44,163,665,2746,11685,50560,222560, 990647,4461545,20261605,92750052,427391693, 1980932854,9228373502,43188083319,202928074526, 956967526605,4527549376056,21483545535985, 102213596708559,487492635095972,2330199032630362, 11161042429983908,53558921980348752] |