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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 25 |
| 4 | 102 |
| 5 | 408 |
| 6 | 1723 |
| 7 | 7320 |
| 8 | 31703 |
| 9 | 138362 |
| 10 | 611103 |
| 11 | 2714012 |
| 12 | 12133531 |
| 13 | 54528943 |
| 14 | 246177191 |
| 15 | 1115631262 |
| 16 | 5074220799 |
| 17 | 23149462838 |
| 18 | 105898900015 |
| 19 | 485654339647 |
| 20 | 2232247005041 |
| 21 | 10281001178927 |
| 22 | 47439927740353 |
| 23 | 219279992251104 |
| 24 | 1015163875320307 |
| 25 | 4706592848028672 |
| 26 | 21850761937459040 |
| 27 | 101571656107705363 |
[1,2,7,25,102,408,1723,7320,31703,138362,611103, 2714012,12133531,54528943,246177191,1115631262, 5074220799,23149462838,105898900015,485654339647, 2232247005041,10281001178927,47439927740353, 219279992251104,1015163875320307,4706592848028672, 21850761937459040,101571656107705363] |