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| n | a(n) |
|---|---|
| 2 | 0 |
| 3 | 1 |
| 4 | 21 |
| 5 | 151 |
| 6 | 615 |
| 7 | 1845 |
| 8 | 4571 |
| 9 | 9926 |
| 10 | 19566 |
| 11 | 35805 |
| 12 | 61765 |
| 13 | 101541 |
| 14 | 160381 |
| 15 | 244881 |
| 16 | 363195 |
| 17 | 525260 |
| 18 | 743036 |
| 19 | 1030761 |
| 20 | 1405221 |
| 21 | 1886035 |
| 22 | 2495955 |
| 23 | 3261181 |
| 24 | 4211691 |
| 25 | 5381586 |
| 26 | 6809450 |
| 27 | 8538725 |
| 28 | 10618101 |
| 29 | 13101921 |
| 30 | 16050601 |
| 31 | 19531065 |
| 32 | 23617195 |
| 33 | 28390296 |
| 34 | 33939576 |
[0,1,21,151,615,1845,4571,9926,19566,35805,61765, 101541,160381,244881,363195,525260,743036,1030761, 1405221,1886035,2495955,3261181,4211691,5381586, 6809450,8538725,10618101,13101921,16050601, 19531065,23617195,28390296,33939576] |