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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 15 |
| 4 | 40 |
| 5 | 89 |
| 6 | 210 |
| 7 | 435 |
| 8 | 919 |
| 9 | 1819 |
| 10 | 3583 |
| 11 | 6719 |
| 12 | 12648 |
| 13 | 22849 |
| 14 | 41074 |
| 15 | 72050 |
| 16 | 125411 |
| 17 | 213620 |
| 18 | 361845 |
| 19 | 601945 |
| 20 | 995074 |
| 21 | 1622338 |
| 22 | 2626342 |
| 23 | 4201367 |
| 24 | 6681992 |
| 25 | 10515756 |
| 26 | 16449852 |
| 27 | 25509952 |
| 28 | 39333476 |
| 29 | 60172701 |
| 30 | 91577517 |
| 31 | 138390481 |
| 32 | 208096282 |
| 33 | 310976731 |
| 34 | 462512831 |
[1,2,6,15,40,89,210,435,919,1819,3583,6719,12648, 22849,41074,72050,125411,213620,361845,601945, 995074,1622338,2626342,4201367,6681992,10515756, 16449852,25509952,39333476,60172701,91577517, 138390481,208096282,310976731,462512831] |