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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 4 |
| 5 | 10 |
| 6 | 20 |
| 7 | 47 |
| 8 | 128 |
| 9 | 340 |
| 10 | 868 |
| 11 | 2275 |
| 12 | 6188 |
| 13 | 16922 |
| 14 | 46112 |
| 15 | 126613 |
| 16 | 351568 |
| 17 | 981622 |
| 18 | 2747876 |
| 19 | 7723250 |
| 20 | 21811856 |
| 21 | 61828886 |
| 22 | 175752728 |
| 23 | 500984606 |
| 24 | 1432111244 |
| 25 | 4104175970 |
| 26 | 11787811340 |
| 27 | 33926475162 |
| 28 | 97837209036 |
| 29 | 282662156478 |
| 30 | 818022923184 |
| 31 | 2371103693427 |
[1,1,1,1,4,10,20,47,128,340,868,2275,6188,16922, 46112,126613,351568,981622,2747876,7723250, 21811856,61828886,175752728,500984606,1432111244, 4104175970,11787811340,33926475162,97837209036, 282662156478,818022923184,2371103693427] |