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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 10 |
| 4 | 39 |
| 5 | 151 |
| 6 | 588 |
| 7 | 2304 |
| 8 | 9111 |
| 9 | 36307 |
| 10 | 145553 |
| 11 | 586246 |
| 12 | 2370264 |
| 13 | 9614242 |
| 14 | 39105580 |
| 15 | 159444160 |
| 16 | 651468967 |
| 17 | 2666771488 |
| 18 | 10934393619 |
| 19 | 44899828056 |
| 20 | 184616878289 |
| 21 | 760010818689 |
| 22 | 3132147583744 |
| 23 | 12921037206764 |
| 24 | 53351800567200 |
| 25 | 220478125956426 |
| 26 | 911839751015196 |
| 27 | 3773836780169050 |
[1,1,3,10,39,151,588,2304,9111,36307,145553, 586246,2370264,9614242,39105580,159444160, 651468967,2666771488,10934393619,44899828056, 184616878289,760010818689,3132147583744, 12921037206764,53351800567200,220478125956426, 911839751015196,3773836780169050] |