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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 4 |
| 5 | 6 |
| 6 | 18 |
| 7 | 35 |
| 8 | 93 |
| 9 | 214 |
| 10 | 549 |
| 11 | 1362 |
| 12 | 3534 |
| 13 | 9102 |
| 14 | 23951 |
| 15 | 63192 |
| 16 | 168561 |
| 17 | 451764 |
| 18 | 1219290 |
| 19 | 3305783 |
| 20 | 9008027 |
| 21 | 24643538 |
| 22 | 67681372 |
| 23 | 186504925 |
| 24 | 515566016 |
| 25 | 1429246490 |
| 26 | 3972598378 |
| 27 | 11068477743 |
| 28 | 30908170493 |
| 29 | 86488245455 |
| 30 | 242481159915 |
| 31 | 681048784377 |
| 32 | 1916051725977 |
| 33 | 5399062619966 |
[0,1,1,4,6,18,35,93,214,549,1362,3534,9102,23951, 63192,168561,451764,1219290,3305783,9008027, 24643538,67681372,186504925,515566016,1429246490, 3972598378,11068477743,30908170493,86488245455, 242481159915,681048784377,1916051725977, 5399062619966] |