n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 15 |
3 | 75 |
4 | 428 |
5 | 2781 |
6 | 20093 |
7 | 159340 |
8 | 1372163 |
9 | 12725447 |
10 | 126238060 |
11 | 1332071241 |
12 | 14881206473 |
13 | 175297058228 |
14 | 2169832010759 |
15 | 28136696433171 |
16 | 381199970284620 |
17 | 5383103100853189 |
18 | 79065882217154085 |
19 | 1205566492711167004 |
20 | 19049651311462785947 |
[1,4,15,75,428,2781,20093,159340,1372163,12725447, 126238060,1332071241,14881206473,175297058228, 2169832010759,28136696433171,381199970284620, 5383103100853189,79065882217154085, 1205566492711167004,19049651311462785947] |