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) |
|---|---|
| 1 | 1 |
| 2 | 5 |
| 3 | 13 |
| 4 | 41 |
| 5 | 103 |
| 6 | 275 |
| 7 | 685 |
| 8 | 2525 |
| 9 | 5221 |
| 10 | 13897 |
| 11 | 32717 |
| 12 | 176145 |
| 13 | 321963 |
| 14 | 1390895 |
| 15 | 2223445 |
| 16 | 3845743 |
| 17 | 10539177 |
| 18 | 76756525 |
| 19 | 147653093 |
| 20 | 808935605 |
| 21 | 934179307 |