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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 19 |
| 5 | 65 |
| 6 | 270 |
| 7 | 1032 |
| 8 | 4492 |
| 9 | 18450 |
| 10 | 83108 |
| 11 | 357568 |
| 12 | 1646051 |
| 13 | 7303719 |
| 14 | 34129741 |
| 15 | 154802470 |
| 16 | 731344818 |
| 17 | 3371564716 |
| 18 | 16060636232 |
| 19 | 74963498719 |
| 20 | 359385701046 |
| 21 | 1693717865991 |
| 22 | 8161243408923 |
| 23 | 38758956077611 |
| 24 | 187529238721081 |
| 25 | 896154414305721 |
| 26 | 4350539897658050 |
| 27 | 20896387246603047 |
| 28 | 101730283552601952 |
[1,1,2,5,19,65,270,1032,4492,18450,83108,357568, 1646051,7303719,34129741,154802470,731344818, 3371564716,16060636232,74963498719,359385701046, 1693717865991,8161243408923,38758956077611, 187529238721081,896154414305721,4350539897658050, 20896387246603047,101730283552601952] |