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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 2 |
| 2 | 8 |
| 3 | 20 |
| 4 | 56 |
| 5 | 152 |
| 6 | 416 |
| 7 | 1136 |
| 8 | 3104 |
| 9 | 8480 |
| 10 | 23168 |
| 11 | 63296 |
| 12 | 172928 |
| 13 | 472448 |
| 14 | 1290752 |
| 15 | 3526400 |
| 16 | 9634304 |
| 17 | 26321408 |
| 18 | 71911424 |
| 19 | 196465664 |
| 20 | 536754176 |
| 21 | 1466439680 |
| 22 | 4006387712 |
| 23 | 10945654784 |
| 24 | 29904084992 |
| 25 | 81699479552 |
| 26 | 223207129088 |
| 27 | 609813217280 |
| 28 | 1666040692736 |
| 29 | 4551707820032 |
[2,2,8,20,56,152,416,1136,3104,8480,23168,63296, 172928,472448,1290752,3526400,9634304,26321408, 71911424,196465664,536754176,1466439680, 4006387712,10945654784,29904084992,81699479552, 223207129088,609813217280,1666040692736, 4551707820032] |