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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 13 |
| 3 | 36 |
| 4 | 93 |
| 5 | 228 |
| 6 | 541 |
| 7 | 1252 |
| 8 | 2845 |
| 9 | 6372 |
| 10 | 14109 |
| 11 | 30948 |
| 12 | 67357 |
| 13 | 145636 |
| 14 | 313117 |
| 15 | 669924 |
| 16 | 1427229 |
| 17 | 3029220 |
| 18 | 6407965 |
| 19 | 13514980 |
| 20 | 28428061 |
| 21 | 59652324 |
| 22 | 124897053 |
| 23 | 260978916 |
| 24 | 544327453 |
| 25 | 1133394148 |
| 26 | 2356266781 |
| 27 | 4891490532 |
| 28 | 10140895005 |
| 29 | 20997617892 |
| 30 | 43426891549 |
[1,4,13,36,93,228,541,1252,2845,6372,14109,30948, 67357,145636,313117,669924,1427229,3029220, 6407965,13514980,28428061,59652324,124897053, 260978916,544327453,1133394148,2356266781, 4891490532,10140895005,20997617892,43426891549] |