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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 12 |
| 3 | 50 |
| 4 | 179 |
| 5 | 661 |
| 6 | 2390 |
| 7 | 8476 |
| 8 | 29909 |
| 9 | 104519 |
| 10 | 362672 |
| 11 | 1251478 |
| 12 | 4295783 |
| 13 | 14680713 |
| 14 | 49976442 |
| 15 | 169541536 |
| 16 | 573390953 |
| 17 | 1933856347 |
| 18 | 6505983668 |
| 19 | 21838288442 |
| 20 | 73152323803 |
| 21 | 244578237373 |
| 22 | 816308965214 |
| 23 | 2720178349156 |
| 24 | 9051042401725 |
| 25 | 30074946103983 |
| 26 | 99806282153592 |
| 27 | 330822581617182 |
[1,3,12,50,179,661,2390,8476,29909,104519,362672, 1251478,4295783,14680713,49976442,169541536, 573390953,1933856347,6505983668,21838288442, 73152323803,244578237373,816308965214, 2720178349156,9051042401725,30074946103983, 99806282153592,330822581617182] |