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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 13 |
| 3 | 16 |
| 4 | 25 |
| 5 | 41 |
| 6 | 74 |
| 7 | 132 |
| 8 | 239 |
| 9 | 437 |
| 10 | 800 |
| 11 | 1468 |
| 12 | 2697 |
| 13 | 4957 |
| 14 | 9114 |
| 15 | 16760 |
| 16 | 30823 |
| 17 | 56689 |
| 18 | 104264 |
| 19 | 191768 |
| 20 | 352713 |
| 21 | 648737 |
| 22 | 1193210 |
| 23 | 2194652 |
| 24 | 4036591 |
| 25 | 7424445 |
| 26 | 13655680 |
| 27 | 25116708 |
| 28 | 46196825 |
| 29 | 84969205 |
| 30 | 156282730 |
| 31 | 287448752 |
| 32 | 528700679 |
| 33 | 972432153 |
[4,13,16,25,41,74,132,239,437,800,1468,2697,4957, 9114,16760,30823,56689,104264,191768,352713, 648737,1193210,2194652,4036591,7424445,13655680, 25116708,46196825,84969205,156282730,287448752, 528700679,972432153] |