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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 19 |
| 4 | 64 |
| 5 | 224 |
| 6 | 805 |
| 7 | 2947 |
| 8 | 10934 |
| 9 | 40975 |
| 10 | 154738 |
| 11 | 587910 |
| 12 | 2244681 |
| 13 | 8605061 |
| 14 | 33099767 |
| 15 | 127687258 |
| 16 | 493796454 |
| 17 | 1913755319 |
| 18 | 7431027611 |
| 19 | 28902878561 |
| 20 | 112585961052 |
| 21 | 439148770623 |
| 22 | 1715009647444 |
| 23 | 6705019714554 |
| 24 | 26240361155821 |
| 25 | 102787164654287 |
| 26 | 402972015656065 |
[1,2,6,19,64,224,805,2947,10934,40975,154738, 587910,2244681,8605061,33099767,127687258, 493796454,1913755319,7431027611,28902878561, 112585961052,439148770623,1715009647444, 6705019714554,26240361155821,102787164654287, 402972015656065] |