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) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 16 |
| 4 | 133 |
| 5 | 1521 |
| 6 | 22184 |
| 7 | 393681 |
| 8 | 8233803 |
| 9 | 198342718 |
| 10 | 5408091155 |
| 11 | 164658043397 |
| 12 | 5537255169582 |
| 13 | 203840528337291 |
| 14 | 8153112960102283 |
| 15 | 352079321494938344 |
| 16 | 16325961781591781401 |
| 17 | 809073412162081974237 |
| 18 | 42674870241038732398720 |
| 19 | 2386963662244981472850709 |