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 | 9 |
| 5 | 39 |
| 6 | 169 |
| 7 | 819 |
| 8 | 3969 |
| 9 | 19719 |
| 10 | 97969 |
| 11 | 489219 |
| 12 | 2442969 |
| 13 | 12211719 |
| 14 | 61042969 |
| 15 | 305199219 |
| 16 | 1525917969 |
| 17 | 7629511719 |
| 18 | 38147167969 |
| 19 | 190735449219 |
| 20 | 953675292969 |
| 21 | 4768374511719 |
| 22 | 23841862792969 |
| 23 | 119209304199219 |
| 24 | 596046472167969 |
| 25 | 2980232312011719 |
| 26 | 14901161315917969 |
| 27 | 74505806335449219 |