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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 23 |
| 4 | 97 |
| 5 | 380 |
| 6 | 1707 |
| 7 | 7232 |
| 8 | 33490 |
| 9 | 148286 |
| 10 | 698883 |
| 11 | 3181169 |
| 12 | 15165513 |
| 13 | 70328453 |
| 14 | 337942000 |
| 15 | 1588039719 |
| 16 | 7674943256 |
| 17 | 36419812699 |
| 18 | 176783893031 |
| 19 | 845159746620 |
| 20 | 4116392557523 |
| 21 | 19794295312882 |
| 22 | 96670463328564 |
| 23 | 467018196971056 |
| 24 | 2285837694491921 |
| 25 | 11084686385891413 |
| 26 | 54353664470314740 |
| 27 | 264397581795913506 |
[1,2,7,23,97,380,1707,7232,33490,148286,698883, 3181169,15165513,70328453,337942000,1588039719, 7674943256,36419812699,176783893031,845159746620, 4116392557523,19794295312882,96670463328564, 467018196971056,2285837694491921, 11084686385891413,54353664470314740, 264397581795913506] |