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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 12 |
| 5 | 57 |
| 6 | 300 |
| 7 | 1697 |
| 8 | 10126 |
| 9 | 62991 |
| 10 | 405247 |
| 11 | 2680901 |
| 12 | 18160444 |
| 13 | 125562250 |
| 14 | 883868590 |
| 15 | 6321838520 |
| 16 | 45869309028 |
| 17 | 337167193262 |
| 18 | 2508018933431 |
| 19 | 18861358215299 |
| 20 | 143293615189089 |
| 21 | 1098997404472941 |
| 22 | 8504070741463729 |
| 23 | 66358269984208701 |
| 24 | 521923129718567918 |
| 25 | 4136089275165532156 |
| 26 | 33013640650845937124 |
[1,1,3,12,57,300,1697,10126,62991,405247,2680901, 18160444,125562250,883868590,6321838520, 45869309028,337167193262,2508018933431, 18861358215299,143293615189089,1098997404472941, 8504070741463729,66358269984208701, 521923129718567918,4136089275165532156, 33013640650845937124] |