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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 20 |
| 4 | 206 |
| 5 | 1282 |
| 6 | 6302 |
| 7 | 26942 |
| 8 | 104948 |
| 9 | 382444 |
| 10 | 1325444 |
| 11 | 4417024 |
| 12 | 14263474 |
| 13 | 44884286 |
| 14 | 138222194 |
| 15 | 417923290 |
| 16 | 1243857480 |
| 17 | 3651728760 |
| 18 | 10592838440 |
| 19 | 30403009612 |
| 20 | 86440264694 |
| 21 | 243689593114 |
| 22 | 681776739174 |
| 23 | 1894276352726 |
| 24 | 5230101132028 |
| 25 | 14357448589988 |