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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 25 |
| 4 | 97 |
| 5 | 404 |
| 6 | 1693 |
| 7 | 7388 |
| 8 | 32505 |
| 9 | 145180 |
| 10 | 657113 |
| 11 | 2989105 |
| 12 | 13746349 |
| 13 | 63477990 |
| 14 | 294979025 |
| 15 | 1377542831 |
| 16 | 6455184517 |
| 17 | 30385998096 |
| 18 | 143414160901 |
| 19 | 679093203299 |
| 20 | 3224102213017 |
| 21 | 15341517413850 |
| 22 | 73177613623841 |
| 23 | 349684935900806 |
| 24 | 1674275884420683 |
| 25 | 8029765418428754 |
| 26 | 38569710367459915 |
| 27 | 185545627362485953 |
[1,2,7,25,97,404,1693,7388,32505,145180,657113, 2989105,13746349,63477990,294979025,1377542831, 6455184517,30385998096,143414160901,679093203299, 3224102213017,15341517413850,73177613623841, 349684935900806,1674275884420683,8029765418428754, 38569710367459915,185545627362485953] |