| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 15 |
| 2 | 90 |
| 3 | 315 |
| 4 | 840 |
| 5 | 1890 |
| 6 | 3780 |
| 7 | 6930 |
| 8 | 11880 |
| 9 | 19305 |
| 10 | 30030 |
| 11 | 45045 |
| 12 | 65520 |
| 13 | 92820 |
| 14 | 128520 |
| 15 | 174420 |
| 16 | 232560 |
| 17 | 305235 |
| 18 | 395010 |
| 19 | 504735 |
| 20 | 637560 |
| 21 | 796950 |
| 22 | 986700 |
| 23 | 1210950 |
| 24 | 1474200 |
| 25 | 1781325 |
| 26 | 2137590 |
| 27 | 2548665 |
| 28 | 3020640 |
| 29 | 3560040 |
| 30 | 4173840 |
| 31 | 4869480 |
| 32 | 5654880 |
| 33 | 6538455 |
| 34 | 7529130 |
[0,15,90,315,840,1890,3780,6930,11880,19305,30030, 45045,65520,92820,128520,174420,232560,305235, 395010,504735,637560,796950,986700,1210950, 1474200,1781325,2137590,2548665,3020640,3560040, 4173840,4869480,5654880,6538455,7529130] |