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 | 4 |
| 3 | 16 |
| 4 | 65 |
| 5 | 267 |
| 6 | 1105 |
| 7 | 4597 |
| 8 | 19196 |
| 9 | 80380 |
| 10 | 337284 |
| 11 | 1417582 |
| 12 | 5965622 |
| 13 | 25130844 |
| 14 | 105954110 |
| 15 | 447015744 |
| 16 | 1886996681 |
| 17 | 7969339643 |
| 18 | 33670068133 |
| 19 | 142301618265 |
| 20 | 601586916703 |
| 21 | 2543852427847 |
| 22 | 10759094481491 |
| 23 | 45513214057191 |