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| n | a(n) |
|---|---|
| 3 | 0 |
| 4 | 0 |
| 5 | 4 |
| 6 | 8 |
| 7 | 4 |
| 8 | 20 |
| 9 | 68 |
| 10 | 108 |
| 11 | 256 |
| 12 | 706 |
| 13 | 1592 |
| 14 | 3592 |
| 15 | 9476 |
| 16 | 23558 |
| 17 | 57164 |
| 18 | 146824 |
| 19 | 382308 |
| 20 | 979768 |
| 21 | 2546128 |
| 22 | 6726610 |
| 23 | 17736940 |
| 24 | 46885242 |
| 25 | 124830600 |
| 26 | 333145774 |
| 27 | 889811108 |
| 28 | 2383411046 |
| 29 | 6398296760 |
| 30 | 17195614290 |
| 31 | 46283797072 |
[0,0,4,8,4,20,68,108,256,706,1592,3592,9476,23558, 57164,146824,382308,979768,2546128,6726610, 17736940,46885242,124830600,333145774,889811108, 2383411046,6398296760,17195614290,46283797072] |