The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 520 |
| 3 | 29565 |
| 4 | 524416 |
| 5 | 4883125 |
| 6 | 30233736 |
| 7 | 141238825 |
| 8 | 536872960 |
| 9 | 1743395481 |
| 10 | 5000005000 |
| 11 | 12968719621 |
| 12 | 30958692480 |
| 13 | 68929260205 |
| 14 | 144627346696 |
| 15 | 288325220625 |
| 16 | 549755846656 |
| 17 | 1007996991985 |
| 18 | 1785233665800 |
| 19 | 3065533194061 |
[0,1,520,29565,524416,4883125,30233736,141238825, 536872960,1743395481,5000005000,12968719621, 30958692480,68929260205,144627346696,288325220625, 549755846656,1007996991985,1785233665800, 3065533194061] |