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 | 4 |
| 2 | 65 |
| 3 | 264 |
| 4 | 4289 |
| 5 | 17420 |
| 6 | 283009 |
| 7 | 1149456 |
| 8 | 18674305 |
| 9 | 75846676 |
| 10 | 1232221121 |
| 11 | 5004731160 |
| 12 | 81307919681 |
| 13 | 330236409884 |
| 14 | 5365090477825 |
| 15 | 21790598321184 |
| 16 | 354014663616769 |
| 17 | 1437849252788260 |
| 18 | 23359602708228929 |
| 19 | 94876260085703976 |
| 20 | 1541379764079492545 |