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 | 3 |
| 3 | 16 |
| 4 | 121 |
| 5 | 1143 |
| 6 | 12570 |
| 7 | 154551 |
| 8 | 2072547 |
| 9 | 29829412 |
| 10 | 455731327 |
| 11 | 7332989616 |
| 12 | 123548350018 |
| 13 | 2169987439342 |
| 14 | 39595583375433 |
| 15 | 748541216196285 |
| 16 | 14628467191450947 |
| 17 | 294984129900772611 |
| 18 | 6128372452917891216 |