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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 27 |
| 4 | 180 |
| 5 | 1015 |
| 6 | 5028 |
| 7 | 23051 |
| 8 | 101272 |
| 9 | 434835 |
| 10 | 1843320 |
| 11 | 7753471 |
| 12 | 32440884 |
| 13 | 135195307 |
| 14 | 561615460 |
| 15 | 2326740315 |
| 16 | 9617256944 |
| 17 | 39671268187 |
| 18 | 163352387952 |
| 19 | 671559953015 |
| 20 | 2756930503420 |
| 21 | 11303415274179 |
| 22 | 46290177094172 |
| 23 | 189368906605747 |
| 24 | 773942488240920 |
| 25 | 3160265160762575 |
| 26 | 12893881856438128 |
| 27 | 52567364492251191 |
| 28 | 214163336821005012 |
| 29 | 871950728486358835 |
| 30 | 3547937446945462500 |
[1,4,27,180,1015,5028,23051,101272,434835,1843320, 7753471,32440884,135195307,561615460,2326740315, 9617256944,39671268187,163352387952,671559953015, 2756930503420,11303415274179,46290177094172, 189368906605747,773942488240920,3160265160762575, 12893881856438128,52567364492251191, 214163336821005012,871950728486358835, 3547937446945462500] |