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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 4 |
| 5 | 5 |
| 6 | 15 |
| 7 | 21 |
| 8 | 56 |
| 9 | 84 |
| 10 | 210 |
| 11 | 330 |
| 12 | 792 |
| 13 | 1287 |
| 14 | 3003 |
| 15 | 5005 |
| 16 | 11440 |
| 17 | 19448 |
| 18 | 43758 |
| 19 | 75582 |
| 20 | 167960 |
| 21 | 293930 |
| 22 | 646646 |
| 23 | 1144066 |
| 24 | 2496144 |
| 25 | 4457400 |
| 26 | 9657700 |
| 27 | 17383860 |
| 28 | 37442160 |
| 29 | 67863915 |
| 30 | 145422675 |
| 31 | 265182525 |
| 32 | 565722720 |
| 33 | 1037158320 |
| 34 | 2203961430 |
| 35 | 4059928950 |
| 36 | 8597496600 |
| 37 | 15905368710 |
| 38 | 33578000610 |
| 39 | 62359143990 |
[0,0,1,1,4,5,15,21,56,84,210,330,792,1287,3003, 5005,11440,19448,43758,75582,167960,293930,646646, 1144066,2496144,4457400,9657700,17383860,37442160, 67863915,145422675,265182525,565722720,1037158320, 2203961430,4059928950,8597496600,15905368710, 33578000610,62359143990] |