n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 15 |
3 | 76 |
4 | 373 |
5 | 2676 |
6 | 17539 |
7 | 152860 |
8 | 1383561 |
9 | 14658148 |
10 | 143131351 |
11 | 2070738924 |
12 | 24754959805 |
13 | 341745565396 |
14 | 5260157782923 |
15 | 92358395065276 |
16 | 1377499388715409 |
17 | 27622124789948100 |
18 | 476285499100204831 |
19 | 10464946811144407948 |
20 | 222724531608924013701 |
[1,4,15,76,373,2676,17539,152860,1383561,14658148, 143131351,2070738924,24754959805,341745565396, 5260157782923,92358395065276,1377499388715409, 27622124789948100,476285499100204831, 10464946811144407948,222724531608924013701] |