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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 2 |
| 3 | 1 |
| 4 | 6 |
| 5 | 6 |
| 6 | 20 |
| 7 | 28 |
| 8 | 72 |
| 9 | 120 |
| 10 | 272 |
| 11 | 496 |
| 12 | 1056 |
| 13 | 2016 |
| 14 | 4160 |
| 15 | 8128 |
| 16 | 16512 |
| 17 | 32640 |
| 18 | 65792 |
| 19 | 130816 |
| 20 | 262656 |
| 21 | 523776 |
| 22 | 1049600 |
| 23 | 2096128 |
| 24 | 4196352 |
| 25 | 8386560 |
| 26 | 16781312 |
| 27 | 33550336 |
| 28 | 67117056 |
| 29 | 134209536 |
| 30 | 268451840 |
| 31 | 536854528 |
| 32 | 1073774592 |
| 33 | 2147450880 |
[1,0,2,1,6,6,20,28,72,120,272,496,1056,2016,4160, 8128,16512,32640,65792,130816,262656,523776, 1049600,2096128,4196352,8386560,16781312,33550336, 67117056,134209536,268451840,536854528,1073774592, 2147450880] |