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) |
|---|---|
| 2 | 9 |
| 3 | 58 |
| 4 | 264 |
| 5 | 1106 |
| 6 | 4495 |
| 7 | 18014 |
| 8 | 71652 |
| 9 | 283760 |
| 10 | 1120806 |
| 11 | 4419928 |
| 12 | 17413572 |
| 13 | 68569666 |
| 14 | 269941451 |
| 15 | 1062631046 |
| 16 | 4183370636 |
| 17 | 16471711736 |
| 18 | 64870158866 |
| 19 | 255541666976 |
| 20 | 1006930883396 |
| 21 | 3968854010936 |
| 22 | 15648092510618 |
| 23 | 61714841143568 |