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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 11 |
| 5 | 34 |
| 6 | 102 |
| 7 | 296 |
| 8 | 851 |
| 9 | 2452 |
| 10 | 7085 |
| 11 | 20489 |
| 12 | 59241 |
| 13 | 171245 |
| 14 | 494973 |
| 15 | 1430710 |
| 16 | 4135527 |
| 17 | 11953991 |
| 18 | 34553692 |
| 19 | 99879234 |
| 20 | 288705927 |
| 21 | 834519021 |
| 22 | 2412219633 |
| 23 | 6972643768 |
| 24 | 20154781952 |
| 25 | 58258423000 |
| 26 | 168398935968 |
| 27 | 486765693153 |
| 28 | 1407021006061 |
| 29 | 4067065818560 |
[1,2,4,11,34,102,296,851,2452,7085,20489,59241, 171245,494973,1430710,4135527,11953991,34553692, 99879234,288705927,834519021,2412219633, 6972643768,20154781952,58258423000,168398935968, 486765693153,1407021006061,4067065818560] |