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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 3 |
| 6 | 6 |
| 7 | 10 |
| 8 | 18 |
| 9 | 39 |
| 10 | 91 |
| 11 | 204 |
| 12 | 435 |
| 13 | 919 |
| 14 | 1992 |
| 15 | 4434 |
| 16 | 9947 |
| 17 | 22215 |
| 18 | 49455 |
| 19 | 110480 |
| 20 | 248505 |
| 21 | 561930 |
| 22 | 1273610 |
| 23 | 2889666 |
| 24 | 6566736 |
| 25 | 14959083 |
| 26 | 34163511 |
| 27 | 78182700 |
| 28 | 179201199 |
| 29 | 411325125 |
| 30 | 945512784 |
| 31 | 2176710450 |
| 32 | 5018195400 |
| 33 | 11583688995 |
| 34 | 26770164919 |
[1,0,0,0,1,3,6,10,18,39,91,204,435,919,1992,4434, 9947,22215,49455,110480,248505,561930,1273610, 2889666,6566736,14959083,34163511,78182700, 179201199,411325125,945512784,2176710450, 5018195400,11583688995,26770164919] |