n | a(n) |
---|---|
2 | 1 |
3 | 2 |
4 | 7 |
5 | 20 |
6 | 59 |
7 | 170 |
8 | 489 |
9 | 1400 |
10 | 4002 |
11 | 11428 |
12 | 32626 |
13 | 93160 |
14 | 266136 |
15 | 760800 |
16 | 2176644 |
17 | 6232896 |
18 | 17864841 |
19 | 51253794 |
20 | 147188535 |
21 | 423098404 |
22 | 1217371023 |
23 | 3505992050 |
24 | 10106384621 |
25 | 29158627592 |
26 | 84200265555 |
27 | 243345531806 |
28 | 703858089717 |
[1,2,7,20,59,170,489,1400,4002,11428,32626,93160, 266136,760800,2176644,6232896,17864841,51253794, 147188535,423098404,1217371023,3505992050, 10106384621,29158627592,84200265555,243345531806, 703858089717] |