This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 15 |
| 3 | 75 |
| 4 | 391 |
| 5 | 2065 |
| 6 | 11091 |
| 7 | 60215 |
| 8 | 330003 |
| 9 | 1820869 |
| 10 | 10103153 |
| 11 | 56313047 |
| 12 | 315071801 |
| 13 | 1768489771 |
| 14 | 9953853677 |
| 15 | 56158682949 |
| 16 | 317505199769 |
| 17 | 1798402412539 |