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 | 3 |
| 4 | 5 |
| 5 | 13 |
| 6 | 37 |
| 7 | 107 |
| 8 | 341 |
| 9 | 1141 |
| 10 | 4021 |
| 11 | 14831 |
| 12 | 57017 |
| 13 | 227617 |
| 14 | 941305 |
| 15 | 4020455 |
| 16 | 17705753 |
| 17 | 80215513 |
| 18 | 373370329 |
| 19 | 1782362219 |
| 20 | 8716939229 |
| 21 | 43615569829 |
| 22 | 223069903933 |
| 23 | 1164867074483 |
| 24 | 6206075782925 |
| 25 | 33702629832685 |
| 26 | 186436337623597 |
| 27 | 1049745170246327 |
| 28 | 6012759489160241 |