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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 2 |
| 3 | 69 |
| 4 | 1572 |
| 5 | 19865 |
| 6 | 153480 |
| 7 | 830802 |
| 8 | 3476144 |
| 9 | 12003462 |
| 10 | 35757630 |
| 11 | 94780235 |
| 12 | 228579252 |
| 13 | 509929719 |
| 14 | 1065625652 |
| 15 | 2106541920 |
| 16 | 3969848640 |
| 17 | 7176749852 |
| 18 | 12509692794 |
| 19 | 21113614017 |
| 20 | 34626453860 |
| 21 | 55344881445 |
| 22 | 86431928352 |
| 23 | 132174030494 |
| 24 | 198295824432 |
| 25 | 292341936450 |
| 26 | 424135940150 |
| 27 | 606327641127 |
| 28 | 855040875444 |
| 29 | 1190635082147 |
| 30 | 1638595028940 |
[0,2,69,1572,19865,153480,830802,3476144,12003462, 35757630,94780235,228579252,509929719,1065625652, 2106541920,3969848640,7176749852,12509692794, 21113614017,34626453860,55344881445,86431928352, 132174030494,198295824432,292341936450, 424135940150,606327641127,855040875444, 1190635082147,1638595028940] |