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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 18 |
| 6 | 106 |
| 7 | 816 |
| 8 | 4292 |
| 9 | 59698 |
| 10 | 594178 |
| 11 | 9066286 |
| 12 | 87498566 |
| 13 | 1784642080 |
| 14 | 20988667064 |
| 15 | 380829128200 |
| 16 | 4301687654136 |
| 17 | 167344151387170 |
| 18 | 2948286694377154 |
| 19 | 81332961594822202 |
| 20 | 1301097749397343978 |
| 21 | 48612398553534689114 |
| 22 | 904790963165201870170 |
| 23 | 26316129785192975106006 |
| 24 | 464241023562098660374014 |
| 25 | 24858620479726716329900336 |
| 26 | 556565016155501619684118816 |
| 27 | 20303230470838234228146518916 |
| 28 | 424323532462258172880428842252 |
[1,1,2,4,18,106,816,4292,59698,594178,9066286, 87498566,1784642080,20988667064,380829128200, 4301687654136,167344151387170,2948286694377154, 81332961594822202,1301097749397343978, 48612398553534689114,904790963165201870170, 26316129785192975106006,464241023562098660374014, 24858620479726716329900336, 556565016155501619684118816, 20303230470838234228146518916, 424323532462258172880428842252] |