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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 7 |
| 3 | 28 |
| 4 | 151 |
| 5 | 803 |
| 6 | 4108 |
| 7 | 22532 |
| 8 | 125449 |
| 9 | 705929 |
| 10 | 4035955 |
| 11 | 23332364 |
| 12 | 136111591 |
| 13 | 800561116 |
| 14 | 4741777880 |
| 15 | 28258286033 |
| 16 | 169322163149 |
| 17 | 1019483819757 |
| 18 | 6164900341534 |
| 19 | 37425357962592 |
| 20 | 228002416106605 |
| 21 | 1393503512669230 |
| 22 | 8541839907812651 |
| 23 | 52500559705299795 |
| 24 | 323483846045526418 |
[1,1,7,28,151,803,4108,22532,125449,705929, 4035955,23332364,136111591,800561116,4741777880, 28258286033,169322163149,1019483819757, 6164900341534,37425357962592,228002416106605, 1393503512669230,8541839907812651, 52500559705299795,323483846045526418] |