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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 3 |
| 3 | 2 |
| 4 | 23 |
| 5 | 35 |
| 6 | 258 |
| 7 | 591 |
| 8 | 3538 |
| 9 | 10378 |
| 10 | 55110 |
| 11 | 189260 |
| 12 | 937965 |
| 13 | 3566795 |
| 14 | 17014249 |
| 15 | 69167067 |
| 16 | 323493034 |
| 17 | 1374890250 |
| 18 | 6373894066 |
| 19 | 27922300363 |
| 20 | 129121327852 |
| 21 | 577728005802 |
| 22 | 2674276420225 |
| 23 | 12149013493835 |
| 24 | 56397695554652 |
| 25 | 259129442571387 |
| 26 | 1207399214941454 |
| 27 | 5596251474948357 |
| 28 | 26180522045526490 |
[1,0,3,2,23,35,258,591,3538,10378,55110,189260, 937965,3566795,17014249,69167067,323493034, 1374890250,6373894066,27922300363,129121327852, 577728005802,2674276420225,12149013493835, 56397695554652,259129442571387,1207399214941454, 5596251474948357,26180522045526490] |