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| n | a(n) |
|---|---|
| 1 | 10 |
| 2 | 28 |
| 3 | 78 |
| 4 | 220 |
| 5 | 618 |
| 6 | 1740 |
| 7 | 4894 |
| 8 | 13772 |
| 9 | 38746 |
| 10 | 109020 |
| 11 | 306734 |
| 12 | 863036 |
| 13 | 2428234 |
| 14 | 6832108 |
| 15 | 19222846 |
| 16 | 54085548 |
| 17 | 152175418 |
| 18 | 428161788 |
| 19 | 1204678734 |
| 20 | 3389491996 |
| 21 | 9536696618 |
| 22 | 26832511756 |
| 23 | 75496129374 |
| 24 | 212416400780 |
| 25 | 597656166170 |
[10,28,78,220,618,1740,4894,13772,38746,109020, 306734,863036,2428234,6832108,19222846,54085548, 152175418,428161788,1204678734,3389491996, 9536696618,26832511756,75496129374,212416400780, 597656166170] |