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 | 1 |
| 3 | 5 |
| 4 | 44 |
| 5 | 519 |
| 6 | 7590 |
| 7 | 132347 |
| 8 | 2689046 |
| 9 | 62644234 |
| 10 | 1651650774 |
| 11 | 48731341965 |
| 12 | 1592908456996 |
| 13 | 57173688136781 |
| 14 | 2235773294509565 |
| 15 | 94608603077007214 |
| 16 | 4306708055122614542 |
| 17 | 209823573154587335730 |
| 18 | 10892496561736261641371 |
| 19 | 600171728539156939466278 |