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) |
|---|---|
| 3 | 1 |
| 4 | 9 |
| 5 | 61 |
| 6 | 381 |
| 7 | 2332 |
| 8 | 14337 |
| 9 | 89497 |
| 10 | 569794 |
| 11 | 3704504 |
| 12 | 24584693 |
| 13 | 166335677 |
| 14 | 1145533650 |
| 15 | 8017098273 |
| 16 | 56928364553 |
| 17 | 409558170361 |
| 18 | 2981386305018 |
| 19 | 21935294881644 |
| 20 | 162951791097669 |
| 21 | 1221201051018189 |
| 22 | 9225637750090023 |
| 23 | 70209505971502533 |
| 24 | 537934326588404973 |