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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 45 |
| 2 | 495 |
| 3 | 3003 |
| 4 | 12870 |
| 5 | 43758 |
| 6 | 125970 |
| 7 | 319770 |
| 8 | 735471 |
| 9 | 1562275 |
| 10 | 3108105 |
| 11 | 5852925 |
| 12 | 10518300 |
| 13 | 18156204 |
| 14 | 30260340 |
| 15 | 48903492 |
| 16 | 76904685 |
| 17 | 118030185 |
| 18 | 177232627 |
| 19 | 260932815 |
| 20 | 377348994 |
| 21 | 536878650 |
| 22 | 752538150 |
| 23 | 1040465790 |
| 24 | 1420494075 |
| 25 | 1916797311 |
| 26 | 2558620845 |
| 27 | 3381098545 |
[1,45,495,3003,12870,43758,125970,319770,735471, 1562275,3108105,5852925,10518300,18156204, 30260340,48903492,76904685,118030185,177232627, 260932815,377348994,536878650,752538150, 1040465790,1420494075,1916797311,2558620845, 3381098545] |