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 | 2 |
| 2 | 7 |
| 3 | 24 |
| 4 | 77 |
| 5 | 238 |
| 6 | 723 |
| 7 | 2180 |
| 8 | 6553 |
| 9 | 19674 |
| 10 | 59039 |
| 11 | 177136 |
| 12 | 531429 |
| 13 | 1594310 |
| 14 | 4782955 |
| 15 | 14348892 |
| 16 | 43046705 |
| 17 | 129140146 |
| 18 | 387420471 |
| 19 | 1162261448 |
| 20 | 3486784381 |
| 21 | 10460353182 |
| 22 | 31381059587 |
| 23 | 94143178804 |
| 24 | 282429536457 |
| 25 | 847288609418 |
| 26 | 2541865828303 |
| 27 | 7625597484960 |
| 28 | 22876792454933 |