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 | 1 |
| 3 | 5 |
| 4 | 20 |
| 5 | 56 |
| 6 | 137 |
| 7 | 295 |
| 8 | 709 |
| 9 | 1983 |
| 10 | 5280 |
| 11 | 13521 |
| 12 | 34173 |
| 13 | 85993 |
| 14 | 219721 |
| 15 | 567894 |
| 16 | 1461417 |
| 17 | 3737198 |
| 18 | 9546206 |
| 19 | 24410323 |
| 20 | 62518425 |
| 21 | 160259301 |
| 22 | 410562684 |
| 23 | 1050999521 |
| 24 | 2690293140 |
| 25 | 6888161028 |
| 26 | 17639430568 |
| 27 | 45173289641 |
| 28 | 115675667529 |