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 | 20 |
| 2 | 400 |
| 3 | 8902 |
| 4 | 197281 |
| 5 | 4865617 |
| 6 | 119060679 |
| 7 | 3195913043 |
| 8 | 84999425906 |
| 9 | 2439540533153 |
| 10 | 69353270203366 |
| 11 | 2097660204806910 |
| 12 | 62855340727822758 |
| 13 | 1981075507583376209 |