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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 23 |
| 5 | 68 |
| 6 | 238 |
| 7 | 808 |
| 8 | 2938 |
| 9 | 10616 |
| 10 | 40028 |
| 11 | 151564 |
| 12 | 586471 |
| 13 | 2283160 |
| 14 | 9027376 |
| 15 | 35968594 |
| 16 | 144723618 |
| 17 | 585936607 |
| 18 | 2390988241 |
| 19 | 9817042075 |
| 20 | 40548235574 |
| 21 | 168289941614 |
| 22 | 701951164497 |
| 23 | 2941244446309 |
| 24 | 12376091360723 |
| 25 | 52267911299832 |
| 26 | 221529445747065 |
| 27 | 942115413840111 |
| 28 | 4019368944366612 |
[1,1,3,7,23,68,238,808,2938,10616,40028,151564, 586471,2283160,9027376,35968594,144723618, 585936607,2390988241,9817042075,40548235574, 168289941614,701951164497,2941244446309, 12376091360723,52267911299832,221529445747065, 942115413840111,4019368944366612] |