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 | 13 |
| 2 | 233 |
| 3 | 4181 |
| 4 | 75025 |
| 5 | 1346269 |
| 6 | 24157817 |
| 7 | 433494437 |
| 8 | 7778742049 |
| 9 | 139583862445 |
| 10 | 2504730781961 |
| 11 | 44945570212853 |
| 12 | 806515533049393 |
| 13 | 14472334024676221 |
| 14 | 259695496911122585 |
| 15 | 4660046610375530309 |
| 16 | 83621143489848422977 |
| 17 | 1500520536206896083277 |
| 18 | 26925748508234281076009 |