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 | 246 |
| 4 | 945 |
| 5 | 3177 |
| 6 | 9648 |
| 7 | 26928 |
| 8 | 70092 |
| 9 | 171820 |
| 10 | 399960 |
| 11 | 889560 |
| 12 | 1900380 |
| 13 | 3915900 |
| 14 | 7811280 |
| 15 | 15129168 |
| 16 | 28526562 |
| 17 | 52480242 |
| 18 | 94386908 |
| 19 | 166242780 |
| 20 | 287179794 |
| 21 | 487227906 |
| 22 | 812840976 |
| 23 | 1334891664 |
| 24 | 2160134700 |