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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 10 |
| 5 | 29 |
| 6 | 86 |
| 7 | 266 |
| 8 | 842 |
| 9 | 2720 |
| 10 | 8924 |
| 11 | 29661 |
| 12 | 99654 |
| 13 | 337902 |
| 14 | 1154814 |
| 15 | 3973848 |
| 16 | 13756956 |
| 17 | 47878802 |
| 18 | 167425436 |
| 19 | 587954324 |
| 20 | 2072659700 |
| 21 | 7331934464 |
| 22 | 26018377112 |
| 23 | 92596633117 |
| 24 | 330415480966 |
| 25 | 1181911210006 |
| 26 | 4237288522870 |
| 27 | 15222929711704 |
| 28 | 54796317032956 |
| 29 | 197601339619494 |
[1,1,1,4,10,29,86,266,842,2720,8924,29661,99654, 337902,1154814,3973848,13756956,47878802, 167425436,587954324,2072659700,7331934464, 26018377112,92596633117,330415480966, 1181911210006,4237288522870,15222929711704, 54796317032956,197601339619494] |