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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 13 |
| 3 | 59 |
| 4 | 181 |
| 5 | 469 |
| 6 | 1107 |
| 7 | 2447 |
| 8 | 5120 |
| 9 | 10197 |
| 10 | 19415 |
| 11 | 35485 |
| 12 | 62501 |
| 13 | 106471 |
| 14 | 175993 |
| 15 | 283101 |
| 16 | 444308 |
| 17 | 681875 |
| 18 | 1025337 |
| 19 | 1513319 |
| 20 | 2195677 |
| 21 | 3136001 |
| 22 | 4414519 |
| 23 | 6131443 |
| 24 | 8410800 |
| 25 | 11404793 |
| 26 | 15298739 |
| 27 | 20316633 |
| 28 | 26727389 |
| 29 | 34851811 |
| 30 | 45070349 |
| 31 | 57831697 |
[4,13,59,181,469,1107,2447,5120,10197,19415,35485, 62501,106471,175993,283101,444308,681875,1025337, 1513319,2195677,3136001,4414519,6131443,8410800, 11404793,15298739,20316633,26727389,34851811, 45070349,57831697] |