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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 0 |
| 4 | 2 |
| 5 | 1 |
| 6 | 5 |
| 7 | 4 |
| 8 | 15 |
| 9 | 15 |
| 10 | 48 |
| 11 | 57 |
| 12 | 162 |
| 13 | 218 |
| 14 | 570 |
| 15 | 842 |
| 16 | 2070 |
| 17 | 3284 |
| 18 | 7709 |
| 19 | 12922 |
| 20 | 29299 |
| 21 | 51255 |
| 22 | 113220 |
| 23 | 204781 |
| 24 | 443574 |
| 25 | 823554 |
| 26 | 1757947 |
| 27 | 3331818 |
| 28 | 7035054 |
| 29 | 13552699 |
| 30 | 28387680 |
| 31 | 55401396 |
| 32 | 115369417 |
| 33 | 227501256 |
| 34 | 471780468 |
| 35 | 938107057 |
| 36 | 1939727280 |
| 37 | 3883120002 |
[1,0,1,0,2,1,5,4,15,15,48,57,162,218,570,842,2070, 3284,7709,12922,29299,51255,113220,204781,443574, 823554,1757947,3331818,7035054,13552699,28387680, 55401396,115369417,227501256,471780468,938107057, 1939727280,3883120002] |