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 | 1 |
| 2 | 3 |
| 3 | 31 |
| 4 | 553 |
| 5 | 14281 |
| 6 | 517681 |
| 7 | 25396561 |
| 8 | 1625662081 |
| 9 | 131681531521 |
| 10 | 13168185811201 |
| 11 | 1593350882323201 |
| 12 | 229442532323558401 |
| 13 | 38775788037405619201 |
| 14 | 7600054456464819148801 |
| 15 | 1710012252722891749632001 |
| 16 | 437763136697374129754112001 |
| 17 | 126513546505546814497787904001 |