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 | 9 |
| 2 | 54 |
| 3 | 255 |
| 4 | 1035 |
| 5 | 3753 |
| 6 | 12483 |
| 7 | 38709 |
| 8 | 113265 |
| 9 | 315445 |
| 10 | 841842 |
| 11 | 2164185 |
| 12 | 5382276 |
| 13 | 12994290 |
| 14 | 30543210 |
| 15 | 70066809 |
| 16 | 157199805 |
| 17 | 345552183 |
| 18 | 745377215 |
| 19 | 1579915080 |
| 20 | 3294664578 |
| 21 | 6766656315 |
| 22 | 13700560491 |
| 23 | 27370137195 |
| 24 | 53991639855 |
| 25 | 105242612526 |
| 26 | 202837976145 |