n | a(n) |
---|---|
1 | 1 |
2 | 0 |
3 | 2 |
4 | 0 |
5 | 15 |
6 | 40 |
7 | 153 |
8 | 480 |
9 | 1841 |
10 | 6528 |
11 | 23901 |
12 | 87040 |
13 | 322875 |
14 | 1198080 |
15 | 4474738 |
16 | 16773120 |
17 | 63164175 |
18 | 238605640 |
19 | 904213989 |
20 | 3435921408 |
21 | 13089461538 |
22 | 49977753600 |
23 | 191219550297 |
24 | 733007052640 |
25 | 2814750270420 |
26 | 10825959997440 |
27 | 41699998413248 |
28 | 160842834247680 |
[1,0,2,0,15,40,153,480,1841,6528,23901,87040, 322875,1198080,4474738,16773120,63164175, 238605640,904213989,3435921408,13089461538, 49977753600,191219550297,733007052640, 2814750270420,10825959997440,41699998413248, 160842834247680] |