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 | 3 |
| 4 | 8 |
| 5 | 25 |
| 6 | 80 |
| 7 | 286 |
| 8 | 1070 |
| 9 | 4280 |
| 10 | 17946 |
| 11 | 78907 |
| 12 | 361248 |
| 13 | 1718001 |
| 14 | 8456130 |
| 15 | 42980034 |
| 16 | 225066289 |
| 17 | 1212028798 |
| 18 | 6701265897 |
| 19 | 37986122037 |
| 20 | 220477639797 |
| 21 | 1308833637621 |
| 22 | 7938564964369 |
| 23 | 49151551028767 |
| 24 | 310388888456536 |
| 25 | 1997635594602629 |
| 26 | 13093695854320203 |
| 27 | 87349973125826943 |