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 | 4 |
| 2 | 19 |
| 3 | 94 |
| 4 | 469 |
| 5 | 2344 |
| 6 | 11719 |
| 7 | 58594 |
| 8 | 292969 |
| 9 | 1464844 |
| 10 | 7324219 |
| 11 | 36621094 |
| 12 | 183105469 |
| 13 | 915527344 |
| 14 | 4577636719 |
| 15 | 22888183594 |
| 16 | 114440917969 |
| 17 | 572204589844 |
| 18 | 2861022949219 |
| 19 | 14305114746094 |
| 20 | 71525573730469 |
| 21 | 357627868652344 |