The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 15 |
| 4 | 61 |
| 5 | 221 |
| 6 | 961 |
| 7 | 3843 |
| 8 | 16691 |
| 9 | 69321 |
| 10 | 309193 |
| 11 | 1326193 |
| 12 | 5933567 |
| 13 | 25855481 |
| 14 | 117273025 |
| 15 | 519449575 |
| 16 | 2361947235 |
| 17 | 10553854571 |
| 18 | 48388079905 |
| 19 | 218345888851 |
| 20 | 1003023976695 |
| 21 | 4551161057929 |
| 22 | 21023406034253 |
| 23 | 96016404138687 |
| 24 | 444214179768713 |
| 25 | 2036543544957007 |
| 26 | 9459583710294399 |
| 27 | 43569389164709415 |
[1,1,5,15,61,221,961,3843,16691,69321,309193, 1326193,5933567,25855481,117273025,519449575, 2361947235,10553854571,48388079905,218345888851, 1003023976695,4551161057929,21023406034253, 96016404138687,444214179768713,2036543544957007, 9459583710294399,43569389164709415] |