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 | 1 |
| 3 | 4 |
| 4 | 19 |
| 5 | 91 |
| 6 | 571 |
| 7 | 4096 |
| 8 | 38599 |
| 9 | 370399 |
| 10 | 3771751 |
| 11 | 40020916 |
| 12 | 486887611 |
| 13 | 6457566259 |
| 14 | 97397627419 |
| 15 | 1566407932636 |
| 16 | 25622476773391 |
| 17 | 416792928270751 |
| 18 | 7346982309720079 |
| 19 | 141863542111338124 |
| 20 | 2968348473040595971 |
| 21 | 65223378275792128771 |
| 22 | 1460499016109864574691 |
| 23 | 32600807940657384926884 |