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 | 4 |
| 2 | 18 |
| 3 | 86 |
| 4 | 426 |
| 5 | 2162 |
| 6 | 11166 |
| 7 | 58438 |
| 8 | 309042 |
| 9 | 1648154 |
| 10 | 8851206 |
| 11 | 47813790 |
| 12 | 259585002 |
| 13 | 1415431266 |
| 14 | 7747200558 |
| 15 | 42545600310 |
| 16 | 234346445154 |
| 17 | 1294260644906 |
| 18 | 7165245015510 |
| 19 | 39754745775886 |
| 20 | 221009855334426 |
| 21 | 1230909476804594 |
| 22 | 6867024985408638 |
| 23 | 38369226561522086 |