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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 11 |
| 4 | 34 |
| 5 | 112 |
| 6 | 376 |
| 7 | 1257 |
| 8 | 4330 |
| 9 | 15068 |
| 10 | 52570 |
| 11 | 185086 |
| 12 | 657128 |
| 13 | 2339972 |
| 14 | 8366910 |
| 15 | 30070119 |
| 16 | 108400594 |
| 17 | 391749772 |
| 18 | 1420203840 |
| 19 | 5161860950 |
| 20 | 18797194292 |
| 21 | 68593029228 |
| 22 | 250803101058 |
| 23 | 918497353314 |
| 24 | 3368841454202 |
| 25 | 12375002551280 |
| 26 | 45518663980004 |
| 27 | 167631635849400 |
| 28 | 618071950062304 |
| 29 | 2281410957097608 |
[1,1,4,11,34,112,376,1257,4330,15068,52570,185086, 657128,2339972,8366910,30070119,108400594, 391749772,1420203840,5161860950,18797194292, 68593029228,250803101058,918497353314, 3368841454202,12375002551280,45518663980004, 167631635849400,618071950062304,2281410957097608] |