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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 21 |
| 3 | 46 |
| 4 | 150 |
| 5 | 488 |
| 6 | 1468 |
| 7 | 4626 |
| 8 | 14720 |
| 9 | 45811 |
| 10 | 143798 |
| 11 | 453581 |
| 12 | 1423094 |
| 13 | 4469903 |
| 14 | 14063611 |
| 15 | 44197158 |
| 16 | 138899518 |
| 17 | 436737933 |
| 18 | 1372924949 |
| 19 | 4315682539 |
| 20 | 13567748610 |
| 21 | 42653241731 |
| 22 | 134086614407 |
| 23 | 421533391249 |
| 24 | 1325188322229 |
| 25 | 4166003679092 |
[4,21,46,150,488,1468,4626,14720,45811,143798, 453581,1423094,4469903,14063611,44197158, 138899518,436737933,1372924949,4315682539, 13567748610,42653241731,134086614407,421533391249, 1325188322229,4166003679092] |