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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 12 |
| 4 | 36 |
| 5 | 105 |
| 6 | 359 |
| 7 | 1234 |
| 8 | 4179 |
| 9 | 15184 |
| 10 | 55991 |
| 11 | 204578 |
| 12 | 771394 |
| 13 | 2964054 |
| 14 | 11327531 |
| 15 | 43884270 |
| 16 | 172977384 |
| 17 | 680790080 |
| 18 | 2693644347 |
| 19 | 10800095655 |
| 20 | 43381674853 |
| 21 | 174545003823 |
| 22 | 708672027933 |
| 23 | 2888280123869 |
| 24 | 11778061217176 |
| 25 | 48301653756423 |
| 26 | 198967324198300 |
| 27 | 820165234102410 |
| 28 | 3391901879073496 |
[1,2,4,12,36,105,359,1234,4179,15184,55991,204578, 771394,2964054,11327531,43884270,172977384, 680790080,2693644347,10800095655,43381674853, 174545003823,708672027933,2888280123869, 11778061217176,48301653756423,198967324198300, 820165234102410,3391901879073496] |