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 | 0 |
| 2 | 1 |
| 3 | 19 |
| 4 | 235 |
| 5 | 2539 |
| 6 | 26119 |
| 7 | 263863 |
| 8 | 2648107 |
| 9 | 26513875 |
| 10 | 265250287 |
| 11 | 2652876847 |
| 12 | 26530008499 |
| 13 | 265304159371 |
| 14 | 2653054879735 |
| 15 | 26530591844071 |
| 16 | 265306057146811 |
| 17 | 2653061016284227 |
| 18 | 26530611583384063 |
| 19 | 265306120353746335 |
| 20 | 2653061217872021443 |
| 21 | 26530612224048411643 |