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 | 2 |
| 3 | 3 |
| 4 | 9 |
| 5 | 21 |
| 6 | 68 |
| 7 | 208 |
| 8 | 730 |
| 9 | 2542 |
| 10 | 9287 |
| 11 | 34053 |
| 12 | 127112 |
| 13 | 476849 |
| 14 | 1803636 |
| 15 | 6851960 |
| 16 | 26157362 |
| 17 | 100211446 |
| 18 | 385239872 |
| 19 | 1485232325 |
| 20 | 5741327939 |
| 21 | 22246061118 |
| 22 | 86383655207 |
| 23 | 336093789246 |
| 24 | 1309999171971 |
| 25 | 5114453234510 |
| 26 | 19998176771431 |
| 27 | 78306018629550 |
| 28 | 307022197845116 |