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| n | a(n) |
|---|---|
| 1 | 16 |
| 2 | 89 |
| 3 | 386 |
| 4 | 1018 |
| 5 | 3048 |
| 6 | 18492 |
| 7 | 94846 |
| 8 | 421570 |
| 9 | 1921284 |
| 10 | 9223705 |
| 11 | 44315956 |
| 12 | 212087178 |
| 13 | 1016717313 |
| 14 | 4884743522 |
| 15 | 23497886916 |
| 16 | 113131217224 |
| 17 | 544897410224 |
| 18 | 2625208400020 |
| 19 | 12651486479761 |
| 20 | 60984492720145 |
| 21 | 294002949964740 |
[16,89,386,1018,3048,18492,94846,421570,1921284, 9223705,44315956,212087178,1016717313,4884743522, 23497886916,113131217224,544897410224, 2625208400020,12651486479761,60984492720145, 294002949964740] |