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 | 7 |
| 2 | 73 |
| 3 | 649 |
| 4 | 5185 |
| 5 | 38881 |
| 6 | 279937 |
| 7 | 1959553 |
| 8 | 13436929 |
| 9 | 90699265 |
| 10 | 604661761 |
| 11 | 3990767617 |
| 12 | 26121388033 |
| 13 | 169789022209 |
| 14 | 1097098297345 |
| 15 | 7052774768641 |
| 16 | 45137758519297 |
| 17 | 287753210560513 |
| 18 | 1828079220031489 |
| 19 | 11577835060199425 |
| 20 | 73123168801259521 |
| 21 | 460675963447934977 |