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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 2 |
| 2 | 40 |
| 3 | 270 |
| 4 | 1088 |
| 5 | 3250 |
| 6 | 7992 |
| 7 | 17150 |
| 8 | 33280 |
| 9 | 59778 |
| 10 | 101000 |
| 11 | 162382 |
| 12 | 250560 |
| 13 | 373490 |
| 14 | 540568 |
| 15 | 762750 |
| 16 | 1052672 |
| 17 | 1424770 |
| 18 | 1895400 |
| 19 | 2482958 |
| 20 | 3208000 |
| 21 | 4093362 |
| 22 | 5164280 |
| 23 | 6448510 |
| 24 | 7976448 |
| 25 | 9781250 |
| 26 | 11898952 |
| 27 | 14368590 |
| 28 | 17232320 |
| 29 | 20535538 |
[0,2,40,270,1088,3250,7992,17150,33280,59778, 101000,162382,250560,373490,540568,762750,1052672, 1424770,1895400,2482958,3208000,4093362,5164280, 6448510,7976448,9781250,11898952,14368590, 17232320,20535538] |