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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 7 |
| 4 | 39 |
| 5 | 69 |
| 6 | 386 |
| 7 | 683 |
| 8 | 3821 |
| 9 | 6761 |
| 10 | 37824 |
| 11 | 66927 |
| 12 | 374419 |
| 13 | 662509 |
| 14 | 3706366 |
| 15 | 6558163 |
| 16 | 36689241 |
| 17 | 64919121 |
| 18 | 363186044 |
| 19 | 642633047 |
| 20 | 3595171199 |
| 21 | 6361411349 |
| 22 | 35588525946 |
| 23 | 62971480443 |
| 24 | 352290088261 |
| 25 | 623353393081 |
| 26 | 3487312356664 |
[1,1,4,7,39,69,386,683,3821,6761,37824,66927, 374419,662509,3706366,6558163,36689241,64919121, 363186044,642633047,3595171199,6361411349, 35588525946,62971480443,352290088261,623353393081, 3487312356664] |