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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 26 |
| 5 | 89 |
| 6 | 317 |
| 7 | 1129 |
| 8 | 4333 |
| 9 | 16375 |
| 10 | 64689 |
| 11 | 255510 |
| 12 | 1031520 |
| 13 | 4176411 |
| 14 | 17235081 |
| 15 | 71002938 |
| 16 | 297843534 |
| 17 | 1246468199 |
| 18 | 5289497067 |
| 19 | 22427668932 |
| 20 | 96117562882 |
| 21 | 411666657671 |
| 22 | 1779870206015 |
| 23 | 7686833020463 |
| 24 | 33480379281149 |
| 25 | 145660650014735 |
| 26 | 638356364542079 |
| 27 | 2795072779720188 |
| 28 | 12315985271310940 |
[1,1,3,8,26,89,317,1129,4333,16375,64689,255510, 1031520,4176411,17235081,71002938,297843534, 1246468199,5289497067,22427668932,96117562882, 411666657671,1779870206015,7686833020463, 33480379281149,145660650014735,638356364542079, 2795072779720188,12315985271310940] |