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| n | a(n) |
|---|---|
| 1 | 52 |
| 2 | 240 |
| 3 | 964 |
| 4 | 3972 |
| 5 | 15556 |
| 6 | 64532 |
| 7 | 248288 |
| 8 | 988964 |
| 9 | 4164356 |
| 10 | 15899248 |
| 11 | 64719124 |
| 12 | 257019652 |
| 13 | 1070118936 |
| 14 | 4197239188 |
| 15 | 16299415152 |
| 16 | 65592597568 |
| 17 | 259741591312 |
| 18 | 1093901323332 |
| 19 | 4233842104068 |
| 20 | 16616683414632 |
| 21 | 70137217092164 |
[52,240,964,3972,15556,64532,248288,988964, 4164356,15899248,64719124,257019652,1070118936, 4197239188,16299415152,65592597568,259741591312, 1093901323332,4233842104068,16616683414632, 70137217092164] |