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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 19 |
| 4 | 65 |
| 5 | 231 |
| 6 | 841 |
| 7 | 3110 |
| 8 | 11628 |
| 9 | 43834 |
| 10 | 166298 |
| 11 | 634140 |
| 12 | 2428336 |
| 13 | 9331688 |
| 14 | 35967462 |
| 15 | 138987715 |
| 16 | 538287881 |
| 17 | 2088842463 |
| 18 | 8119916647 |
| 19 | 31613327405 |
| 20 | 123251518641 |
| 21 | 481125828853 |
| 22 | 1880262896537 |
| 23 | 7355767408395 |
| 24 | 28803717914791 |
| 25 | 112887697489907 |
| 26 | 442784607413427 |
[1,2,6,19,65,231,841,3110,11628,43834,166298, 634140,2428336,9331688,35967462,138987715, 538287881,2088842463,8119916647,31613327405, 123251518641,481125828853,1880262896537, 7355767408395,28803717914791,112887697489907, 442784607413427] |