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 | 25 |
| 3 | 199 |
| 4 | 1876 |
| 5 | 20257 |
| 6 | 245017 |
| 7 | 3266914 |
| 8 | 47450923 |
| 9 | 743935375 |
| 10 | 12497579698 |
| 11 | 223619318215 |
| 12 | 4240423494685 |
| 13 | 84855613320004 |
| 14 | 1785410320771933 |
| 15 | 39373503608087299 |
| 16 | 907548770965519660 |
| 17 | 21810536356271794549 |
| 18 | 545305573054110017125 |
| 19 | 14155835044848094831018 |