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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 6 |
| 4 | 19 |
| 5 | 52 |
| 6 | 177 |
| 7 | 572 |
| 8 | 2084 |
| 9 | 7356 |
| 10 | 28195 |
| 11 | 105124 |
| 12 | 417624 |
| 13 | 1619699 |
| 14 | 6604938 |
| 15 | 26401947 |
| 16 | 109851101 |
| 17 | 449617572 |
| 18 | 1901123505 |
| 19 | 7928975462 |
| 20 | 33972903518 |
| 21 | 143863241757 |
| 22 | 623248679117 |
| 23 | 2672552178002 |
| 24 | 11686567394545 |
| 25 | 50642455771423 |
| 26 | 223218947010424 |
| 27 | 975963035154683 |
| 28 | 4331396484379463 |
[1,1,3,6,19,52,177,572,2084,7356,28195,105124, 417624,1619699,6604938,26401947,109851101, 449617572,1901123505,7928975462,33972903518, 143863241757,623248679117,2672552178002, 11686567394545,50642455771423,223218947010424, 975963035154683,4331396484379463] |