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| n | a(n) |
|---|---|
| 4 | 48 |
| 5 | 240 |
| 6 | 1045 |
| 7 | 4128 |
| 8 | 15225 |
| 9 | 53424 |
| 10 | 180576 |
| 11 | 592900 |
| 12 | 1902241 |
| 13 | 5989248 |
| 14 | 18564793 |
| 15 | 56791280 |
| 16 | 171782160 |
| 17 | 514566528 |
| 18 | 1528298725 |
| 19 | 4505245344 |
| 20 | 13192832001 |
| 21 | 38403822600 |
| 22 | 111195838656 |
| 23 | 320408071588 |
| 24 | 919203450913 |
| 25 | 2626517214720 |
| 26 | 7477481038225 |
| 27 | 21216084771128 |
| 28 | 60009979734000 |
| 29 | 169250827737264 |
[48,240,1045,4128,15225,53424,180576,592900, 1902241,5989248,18564793,56791280,171782160, 514566528,1528298725,4505245344,13192832001, 38403822600,111195838656,320408071588, 919203450913,2626517214720,7477481038225, 21216084771128,60009979734000,169250827737264] |