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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 10 |
| 4 | 31 |
| 5 | 79 |
| 6 | 224 |
| 7 | 646 |
| 8 | 1784 |
| 9 | 5010 |
| 10 | 14026 |
| 11 | 39283 |
| 12 | 110214 |
| 13 | 308476 |
| 14 | 864321 |
| 15 | 2421872 |
| 16 | 6784237 |
| 17 | 19008032 |
| 18 | 53250952 |
| 19 | 149186453 |
| 20 | 417966045 |
| 21 | 1170955616 |
| 22 | 3280543940 |
| 23 | 9190733824 |
| 24 | 25748605578 |
| 25 | 72137045260 |
| 26 | 202098106485 |
| 27 | 566195445452 |
[1,4,10,31,79,224,646,1784,5010,14026,39283, 110214,308476,864321,2421872,6784237,19008032, 53250952,149186453,417966045,1170955616, 3280543940,9190733824,25748605578,72137045260, 202098106485,566195445452] |