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 | 19 |
| 4 | 69 |
| 5 | 250 |
| 6 | 907 |
| 7 | 3292 |
| 8 | 11949 |
| 9 | 43371 |
| 10 | 157422 |
| 11 | 571388 |
| 12 | 2073943 |
| 13 | 7527704 |
| 14 | 27322992 |
| 15 | 99173120 |
| 16 | 359964521 |
| 17 | 1306548149 |
| 18 | 4742323107 |
| 19 | 17213011605 |
| 20 | 62477347458 |
| 21 | 226771411939 |
| 22 | 823102698260 |
| 23 | 2987581397893 |
| 24 | 10843899100203 |