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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 19 |
| 5 | 51 |
| 6 | 140 |
| 7 | 386 |
| 8 | 1071 |
| 9 | 2983 |
| 10 | 8338 |
| 11 | 23376 |
| 12 | 65715 |
| 13 | 185199 |
| 14 | 523134 |
| 15 | 1480872 |
| 16 | 4200411 |
| 17 | 11936619 |
| 18 | 33981063 |
| 19 | 96897759 |
| 20 | 276739029 |
| 21 | 791532973 |
| 22 | 2267119660 |
| 23 | 6502108902 |
| 24 | 18671460905 |
| 25 | 53680763201 |
| 26 | 154507444731 |
| 27 | 445190930863 |
| 28 | 1284064525987 |
[1,1,3,7,19,51,140,386,1071,2983,8338,23376,65715, 185199,523134,1480872,4200411,11936619,33981063, 96897759,276739029,791532973,2267119660, 6502108902,18671460905,53680763201,154507444731, 445190930863,1284064525987] |