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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 5 |
| 3 | 1 |
| 4 | 36 |
| 5 | 15 |
| 6 | 228 |
| 7 | 231 |
| 8 | 1313 |
| 9 | 1939 |
| 10 | 6971 |
| 11 | 11899 |
| 12 | 33118 |
| 13 | 59543 |
| 14 | 140620 |
| 15 | 254476 |
| 16 | 538042 |
| 17 | 959028 |
| 18 | 1871808 |
| 19 | 3258512 |
| 20 | 5981444 |
| 21 | 10140360 |
| 22 | 17726166 |
| 23 | 29257848 |
| 24 | 49127549 |
| 25 | 79032258 |
| 26 | 128267727 |
| 27 | 201437596 |
[1,0,5,1,36,15,228,231,1313,1939,6971,11899,33118, 59543,140620,254476,538042,959028,1871808,3258512, 5981444,10140360,17726166,29257848,49127549, 79032258,128267727,201437596] |