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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 11 |
| 4 | 36 |
| 5 | 119 |
| 6 | 407 |
| 7 | 1418 |
| 8 | 5018 |
| 9 | 17971 |
| 10 | 64989 |
| 11 | 236915 |
| 12 | 869518 |
| 13 | 3209735 |
| 14 | 11907644 |
| 15 | 44368636 |
| 16 | 165957615 |
| 17 | 622880402 |
| 18 | 2345005449 |
| 19 | 8852862717 |
| 20 | 33505203060 |
| 21 | 127096279124 |
| 22 | 483127286394 |
| 23 | 1840030664115 |
| 24 | 7020349647422 |
[1,1,4,11,36,119,407,1418,5018,17971,64989,236915, 869518,3209735,11907644,44368636,165957615, 622880402,2345005449,8852862717,33505203060, 127096279124,483127286394,1840030664115, 7020349647422] |