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 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 25 |
| 5 | 73 |
| 6 | 283 |
| 7 | 911 |
| 8 | 3697 |
| 9 | 12561 |
| 10 | 52467 |
| 11 | 184471 |
| 12 | 785929 |
| 13 | 2829401 |
| 14 | 12229259 |
| 15 | 44795167 |
| 16 | 195742177 |
| 17 | 726541345 |
| 18 | 3202144483 |
| 19 | 12010174247 |
| 20 | 53300753657 |
| 21 | 201608659561 |
| 22 | 899838791419 |
| 23 | 3427434566831 |
| 24 | 15370709035601 |
| 25 | 58890032580913 |