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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 19 |
| 4 | 65 |
| 5 | 233 |
| 6 | 865 |
| 7 | 3301 |
| 8 | 12875 |
| 9 | 51117 |
| 10 | 205976 |
| 11 | 840429 |
| 12 | 3466108 |
| 13 | 14428533 |
| 14 | 60553582 |
| 15 | 255966778 |
| 16 | 1088958246 |
| 17 | 4659451357 |
| 18 | 20040555293 |
| 19 | 86601741731 |
| 20 | 375841271002 |
| 21 | 1637517304050 |
| 22 | 7160331688467 |
| 23 | 31414117679299 |
| 24 | 138246342300698 |
| 25 | 610132138587868 |
| 26 | 2699915527292424 |
| 27 | 11977212862937455 |
[1,2,6,19,65,233,865,3301,12875,51117,205976, 840429,3466108,14428533,60553582,255966778, 1088958246,4659451357,20040555293,86601741731, 375841271002,1637517304050,7160331688467, 31414117679299,138246342300698,610132138587868, 2699915527292424,11977212862937455] |