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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 25 |
| 3 | 70 |
| 4 | 205 |
| 5 | 614 |
| 6 | 1860 |
| 7 | 5631 |
| 8 | 17034 |
| 9 | 51507 |
| 10 | 155755 |
| 11 | 471038 |
| 12 | 1424553 |
| 13 | 4308225 |
| 14 | 13029159 |
| 15 | 39403450 |
| 16 | 119165999 |
| 17 | 360388207 |
| 18 | 1089905354 |
| 19 | 3296150132 |
| 20 | 9968393611 |
| 21 | 30146949453 |
| 22 | 91172018210 |
| 23 | 275727297765 |
| 24 | 833869252932 |
| 25 | 2521832029371 |
[4,25,70,205,614,1860,5631,17034,51507,155755, 471038,1424553,4308225,13029159,39403450, 119165999,360388207,1089905354,3296150132, 9968393611,30146949453,91172018210,275727297765, 833869252932,2521832029371] |