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 | 8 |
| 3 | 55 |
| 4 | 364 |
| 5 | 2380 |
| 6 | 15504 |
| 7 | 100947 |
| 8 | 657800 |
| 9 | 4292145 |
| 10 | 28048800 |
| 11 | 183579396 |
| 12 | 1203322288 |
| 13 | 7898654920 |
| 14 | 51915526432 |
| 15 | 341643774795 |
| 16 | 2250829575120 |
| 17 | 14844575908435 |
| 18 | 97997533741800 |
| 19 | 647520696018735 |
| 20 | 4282083008118300 |