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| n | a(n) |
|---|---|
| 5 | 1 |
| 6 | 5 |
| 7 | 20 |
| 8 | 70 |
| 9 | 230 |
| 10 | 721 |
| 11 | 2200 |
| 12 | 6575 |
| 13 | 19385 |
| 14 | 56575 |
| 15 | 163952 |
| 16 | 472645 |
| 17 | 1357550 |
| 18 | 3888820 |
| 19 | 11119325 |
| 20 | 31753269 |
| 21 | 90603650 |
| 22 | 258401245 |
| 23 | 736796675 |
| 24 | 2100818555 |
| 25 | 5990757124 |
| 26 | 17087376630 |
| 27 | 48753542665 |
| 28 | 139155765455 |
| 29 | 397356692275 |
| 30 | 1135163887190 |
| 31 | 3244482184720 |
| 32 | 9277856948255 |
[1,5,20,70,230,721,2200,6575,19385,56575,163952, 472645,1357550,3888820,11119325,31753269,90603650, 258401245,736796675,2100818555,5990757124, 17087376630,48753542665,139155765455,397356692275, 1135163887190,3244482184720,9277856948255] |