The OEIS is supported by the many generous donors to the OEIS Foundation.
Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 18 |
| 5 | 53 |
| 6 | 158 |
| 7 | 486 |
| 8 | 1550 |
| 9 | 5109 |
| 10 | 17298 |
| 11 | 59799 |
| 12 | 210048 |
| 13 | 746983 |
| 14 | 2682618 |
| 15 | 9711214 |
| 16 | 35390422 |
| 17 | 129710309 |
| 18 | 477769754 |
| 19 | 1767525315 |
| 20 | 6564644688 |
| 21 | 24467315575 |
| 22 | 91484660770 |
| 23 | 343063807931 |
| 24 | 1289912535908 |
| 25 | 4861963178643 |
| 26 | 18367386626558 |
| 27 | 69533618024841 |
| 28 | 263748085968060 |
[1,2,6,18,53,158,486,1550,5109,17298,59799,210048, 746983,2682618,9711214,35390422,129710309, 477769754,1767525315,6564644688,24467315575, 91484660770,343063807931,1289912535908, 4861963178643,18367386626558,69533618024841, 263748085968060] |