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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 5 |
| 2 | 20 |
| 3 | 65 |
| 4 | 190 |
| 5 | 502 |
| 6 | 1245 |
| 7 | 2910 |
| 8 | 6505 |
| 9 | 13965 |
| 10 | 29005 |
| 11 | 58455 |
| 12 | 114810 |
| 13 | 220240 |
| 14 | 413775 |
| 15 | 762635 |
| 16 | 1381550 |
| 17 | 2463060 |
| 18 | 4327445 |
| 19 | 7500260 |
| 20 | 12836645 |
| 21 | 21712470 |
| 22 | 36323930 |
| 23 | 60143320 |
| 24 | 98620425 |
| 25 | 160238035 |
| 26 | 258110955 |
| 27 | 412367705 |
| 28 | 653709340 |
| 29 | 1028658150 |
| 30 | 1607306688 |
[1,5,20,65,190,502,1245,2910,6505,13965,29005, 58455,114810,220240,413775,762635,1381550,2463060, 4327445,7500260,12836645,21712470,36323930, 60143320,98620425,160238035,258110955,412367705, 653709340,1028658150,1607306688] |