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 | 4 |
| 3 | 25 |
| 4 | 211 |
| 5 | 2236 |
| 6 | 28471 |
| 7 | 422899 |
| 8 | 7173580 |
| 9 | 136750051 |
| 10 | 2893057381 |
| 11 | 67241818876 |
| 12 | 1702829138209 |
| 13 | 46659181547785 |
| 14 | 1375237342827076 |
| 15 | 43380198327693361 |
| 16 | 1458027134026128691 |
| 17 | 52014149849253158284 |
| 18 | 1962794208713975883415 |