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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 10 |
| 6 | 27 |
| 7 | 74 |
| 8 | 226 |
| 9 | 710 |
| 10 | 2354 |
| 11 | 8010 |
| 12 | 28189 |
| 13 | 101094 |
| 14 | 370119 |
| 15 | 1375198 |
| 16 | 5181003 |
| 17 | 19740940 |
| 18 | 75990173 |
| 19 | 295100800 |
| 20 | 1155106357 |
| 21 | 4553312866 |
| 22 | 18063117153 |
| 23 | 72069297826 |
| 24 | 289053128879 |
| 25 | 1164870009786 |
| 26 | 4714970819402 |
| 27 | 19161572076550 |
| 28 | 78162885020942 |
| 29 | 319940035684684 |
| 30 | 1313799822309748 |
[0,1,2,4,10,27,74,226,710,2354,8010,28189,101094, 370119,1375198,5181003,19740940,75990173, 295100800,1155106357,4553312866,18063117153, 72069297826,289053128879,1164870009786, 4714970819402,19161572076550,78162885020942, 319940035684684,1313799822309748] |