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 | 2 |
| 2 | 5 |
| 3 | 13 |
| 4 | 34 |
| 5 | 136 |
| 6 | 666 |
| 7 | 3577 |
| 8 | 23353 |
| 9 | 200704 |
| 10 | 2062593 |
| 11 | 24878084 |
| 12 | 373006265 |
| 13 | 6917185552 |
| 14 | 153624835953 |
| 15 | 4155902941554 |
| 16 | 138450383756352 |
| 17 | 5602635336941568 |
| 18 | 274540864716936000 |
| 19 | 16486029239132118530 |
| 20 | 1209110712606533552257 |