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 | 15 |
| 4 | 82 |
| 5 | 495 |
| 6 | 3144 |
| 7 | 20875 |
| 8 | 142773 |
| 9 | 1000131 |
| 10 | 7136812 |
| 11 | 51702231 |
| 12 | 379234623 |
| 13 | 2810874950 |
| 14 | 21020047557 |
| 15 | 158398829121 |
| 16 | 1201617201230 |
| 17 | 9169060501023 |
| 18 | 70329406653879 |
| 19 | 541949364313821 |
| 20 | 4193569906262874 |
| 21 | 32571403998781956 |
| 22 | 253842927519362734 |
| 23 | 1984442128649393178 |