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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 12 |
| 3 | 20 |
| 4 | 39 |
| 5 | 110 |
| 6 | 245 |
| 7 | 572 |
| 8 | 1384 |
| 9 | 3267 |
| 10 | 7767 |
| 11 | 18500 |
| 12 | 43949 |
| 13 | 104584 |
| 14 | 248880 |
| 15 | 591971 |
| 16 | 1408452 |
| 17 | 3351213 |
| 18 | 7973189 |
| 19 | 18970293 |
| 20 | 45135581 |
| 21 | 107389830 |
| 22 | 255510579 |
| 23 | 607930774 |
| 24 | 1446436781 |
| 25 | 3441480653 |
| 26 | 8188250475 |
| 27 | 19482148534 |
| 28 | 46353514855 |
| 29 | 110288063427 |
[4,12,20,39,110,245,572,1384,3267,7767,18500, 43949,104584,248880,591971,1408452,3351213, 7973189,18970293,45135581,107389830,255510579, 607930774,1446436781,3441480653,8188250475, 19482148534,46353514855,110288063427] |