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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 10 |
| 5 | 28 |
| 6 | 64 |
| 7 | 168 |
| 8 | 396 |
| 9 | 980 |
| 10 | 2348 |
| 11 | 5740 |
| 12 | 13780 |
| 13 | 33460 |
| 14 | 80612 |
| 15 | 194992 |
| 16 | 470424 |
| 17 | 1136688 |
| 18 | 2743160 |
| 19 | 6625108 |
| 20 | 15992040 |
| 21 | 38613792 |
| 22 | 93216616 |
| 23 | 225058680 |
| 24 | 543325464 |
| 25 | 1311738092 |
| 26 | 3166782500 |
| 27 | 7645369060 |
| 28 | 18457475260 |
| 29 | 44560482148 |
| 30 | 107578322912 |
| 31 | 259717522848 |
[1,1,4,10,28,64,168,396,980,2348,5740,13780,33460, 80612,194992,470424,1136688,2743160,6625108, 15992040,38613792,93216616,225058680,543325464, 1311738092,3166782500,7645369060,18457475260, 44560482148,107578322912,259717522848] |