n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 4 |
3 | 9 |
4 | 52 |
5 | 138 |
6 | 904 |
7 | 2581 |
8 | 18020 |
9 | 53622 |
10 | 389112 |
11 | 1189146 |
12 | 8855560 |
13 | 27571156 |
14 | 209174544 |
15 | 660249549 |
16 | 5079702852 |
17 | 16203796158 |
18 | 126033559960 |
19 | 405408758062 |
20 | 3180991167640 |
21 | 10301855821452 |
22 | 81414086371696 |
23 | 265150389430914 |
24 | 2108026107021224 |
25 | 6897985805906972 |
26 | 55119920086104496 |
[1,1,4,9,52,138,904,2581,18020,53622,389112, 1189146,8855560,27571156,209174544,660249549, 5079702852,16203796158,126033559960,405408758062, 3180991167640,10301855821452,81414086371696, 265150389430914,2108026107021224,6897985805906972, 55119920086104496] |