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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 14 |
| 2 | 90 |
| 3 | 390 |
| 4 | 1320 |
| 5 | 3762 |
| 6 | 9438 |
| 7 | 21450 |
| 8 | 45045 |
| 9 | 88660 |
| 10 | 165308 |
| 11 | 294372 |
| 12 | 503880 |
| 13 | 833340 |
| 14 | 1337220 |
| 15 | 2089164 |
| 16 | 3187041 |
| 17 | 4758930 |
| 18 | 6970150 |
| 19 | 10031450 |
| 20 | 14208480 |
| 21 | 19832670 |
| 22 | 27313650 |
| 23 | 37153350 |
| 24 | 49961925 |
| 25 | 66475656 |
| 26 | 87576984 |
| 27 | 114316840 |
[1,14,90,390,1320,3762,9438,21450,45045,88660, 165308,294372,503880,833340,1337220,2089164, 3187041,4758930,6970150,10031450,14208480, 19832670,27313650,37153350,49961925,66475656, 87576984,114316840] |