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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 15 |
| 3 | 47 |
| 4 | 130 |
| 5 | 330 |
| 6 | 784 |
| 7 | 1765 |
| 8 | 3804 |
| 9 | 7898 |
| 10 | 15880 |
| 11 | 31048 |
| 12 | 59220 |
| 13 | 110484 |
| 14 | 202070 |
| 15 | 362974 |
| 16 | 641368 |
| 17 | 1116325 |
| 18 | 1916184 |
| 19 | 3247088 |
| 20 | 5436972 |
| 21 | 9002752 |
| 22 | 14752316 |
| 23 | 23938188 |
| 24 | 38487496 |
| 25 | 61344055 |
| 26 | 96974176 |
| 27 | 152110204 |
| 28 | 236837795 |
| 29 | 366177506 |
| 30 | 562373990 |
| 31 | 858193804 |
| 32 | 1301654610 |
[1,4,15,47,130,330,784,1765,3804,7898,15880,31048, 59220,110484,202070,362974,641368,1116325,1916184, 3247088,5436972,9002752,14752316,23938188, 38487496,61344055,96974176,152110204,236837795, 366177506,562373990,858193804,1301654610] |