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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 12 |
| 4 | 31 |
| 5 | 78 |
| 6 | 208 |
| 7 | 551 |
| 8 | 1502 |
| 9 | 4117 |
| 10 | 11435 |
| 11 | 31926 |
| 12 | 89829 |
| 13 | 253727 |
| 14 | 719926 |
| 15 | 2048919 |
| 16 | 5848543 |
| 17 | 16732592 |
| 18 | 47973762 |
| 19 | 137788720 |
| 20 | 396393362 |
| 21 | 1141962118 |
| 22 | 3294080424 |
| 23 | 9512949813 |
| 24 | 27501182865 |
| 25 | 79579492065 |
| 26 | 230478715333 |
[1,2,5,12,31,78,208,551,1502,4117,11435,31926, 89829,253727,719926,2048919,5848543,16732592, 47973762,137788720,396393362,1141962118, 3294080424,9512949813,27501182865,79579492065, 230478715333] |