n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 9 |
3 | 36 |
4 | 148 |
5 | 489 |
6 | 1959 |
7 | 6326 |
8 | 22741 |
9 | 74072 |
10 | 246436 |
11 | 781189 |
12 | 2523042 |
13 | 7773342 |
14 | 24200874 |
15 | 73439472 |
16 | 222247101 |
17 | 660405663 |
18 | 1958564056 |
19 | 5715567301 |
20 | 16623600991 |
21 | 47780474694 |
22 | 136623175876 |
23 | 386983158080 |
24 | 1090779014163 |
25 | 3048348195528 |
26 | 8478106666045 |
[1,1,9,36,148,489,1959,6326,22741,74072,246436, 781189,2523042,7773342,24200874,73439472, 222247101,660405663,1958564056,5715567301, 16623600991,47780474694,136623175876,386983158080, 1090779014163,3048348195528,8478106666045] |