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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 2 |
| 4 | 2 |
| 5 | 6 |
| 6 | 12 |
| 7 | 22 |
| 8 | 42 |
| 9 | 78 |
| 10 | 140 |
| 11 | 252 |
| 12 | 448 |
| 13 | 788 |
| 14 | 1380 |
| 15 | 2402 |
| 16 | 4158 |
| 17 | 7170 |
| 18 | 12316 |
| 19 | 21082 |
| 20 | 35982 |
| 21 | 61246 |
| 22 | 103992 |
| 23 | 176184 |
| 24 | 297888 |
| 25 | 502728 |
| 26 | 846984 |
| 27 | 1424738 |
| 28 | 2393114 |
| 29 | 4014270 |
| 30 | 6725196 |
| 31 | 11253694 |
| 32 | 18810930 |
| 33 | 31410894 |
| 34 | 52400132 |
| 35 | 87335604 |
| 36 | 145438624 |
| 37 | 242001692 |
[0,0,0,2,2,6,12,22,42,78,140,252,448,788,1380, 2402,4158,7170,12316,21082,35982,61246,103992, 176184,297888,502728,846984,1424738,2393114, 4014270,6725196,11253694,18810930,31410894, 52400132,87335604,145438624,242001692] |