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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 10 |
| 5 | 37 |
| 6 | 144 |
| 7 | 593 |
| 8 | 2515 |
| 9 | 10975 |
| 10 | 48847 |
| 11 | 221071 |
| 12 | 1013886 |
| 13 | 4702530 |
| 14 | 22017327 |
| 15 | 103925505 |
| 16 | 494000139 |
| 17 | 2362666375 |
| 18 | 11361442399 |
| 19 | 54898445359 |
| 20 | 266417109839 |
| 21 | 1297935216161 |
| 22 | 6345598010686 |
| 23 | 31123068382020 |
| 24 | 153095423135329 |
| 25 | 755103728856195 |
| 26 | 3733557839325332 |
[0,1,1,3,10,37,144,593,2515,10975,48847,221071, 1013886,4702530,22017327,103925505,494000139, 2362666375,11361442399,54898445359,266417109839, 1297935216161,6345598010686,31123068382020, 153095423135329,755103728856195,3733557839325332] |