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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 30 |
| 3 | 126 |
| 4 | 534 |
| 5 | 2214 |
| 6 | 9246 |
| 7 | 38142 |
| 8 | 157974 |
| 9 | 649086 |
| 10 | 2675022 |
| 11 | 10966470 |
| 12 | 45054630 |
| 13 | 184400910 |
| 14 | 755930958 |
| 15 | 3089851782 |
| 16 | 12645783414 |
| 17 | 51635728518 |
| 18 | 211059485310 |
| 19 | 861083848998 |
| 20 | 3516072837894 |
| 21 | 14334995983614 |
| 22 | 58485689950254 |
[1,6,30,126,534,2214,9246,38142,157974,649086, 2675022,10966470,45054630,184400910,755930958, 3089851782,12645783414,51635728518,211059485310, 861083848998,3516072837894,14334995983614, 58485689950254] |