The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | -1 |
| 3 | 3 |
| 4 | 0 |
| 5 | -5 |
| 6 | 15 |
| 7 | 0 |
| 8 | -28 |
| 9 | 84 |
| 10 | 0 |
| 11 | -165 |
| 12 | 495 |
| 13 | 0 |
| 14 | -1001 |
| 15 | 3003 |
| 16 | 0 |
| 17 | -6188 |
| 18 | 18564 |
| 19 | 0 |
| 20 | -38760 |
| 21 | 116280 |
| 22 | 0 |
| 23 | -245157 |
| 24 | 735471 |
| 25 | 0 |
| 26 | -1562275 |
| 27 | 4686825 |
| 28 | 0 |
| 29 | -10015005 |
| 30 | 30045015 |
| 31 | 0 |
| 32 | -64512240 |
| 33 | 193536720 |
| 34 | 0 |
| 35 | -417225900 |
| 36 | 1251677700 |
| 37 | 0 |
| 38 | -2707475148 |
| 39 | 8122425444 |
| 40 | 0 |
| 41 | -17620076360 |
[1,0,-1,3,0,-5,15,0,-28,84,0,-165,495,0,-1001, 3003,0,-6188,18564,0,-38760,116280,0,-245157, 735471,0,-1562275,4686825,0,-10015005,30045015,0, -64512240,193536720,0,-417225900,1251677700,0, -2707475148,8122425444,0,-17620076360] |