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 | 2 |
| 3 | 5 |
| 4 | 17 |
| 5 | 90 |
| 6 | 737 |
| 7 | 9671 |
| 8 | 203828 |
| 9 | 6939823 |
| 10 | 381894093 |
| 11 | 33995514100 |
| 12 | 4895735924493 |
| 13 | 1140740465920969 |
| 14 | 430064051388129806 |
| 15 | 262340212087225102629 |
| 16 | 258930219394142564424629 |
| 17 | 413511822712657762611235142 |
| 18 | 1068514808819727052729996031557 |
| 19 | 4467460829187101520121876019174959 |