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 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 11 |
| 4 | 122 |
| 5 | 2278 |
| 6 | 17502 |
| 7 | 140037 |
| 8 | 1250890 |
| 9 | 11184764 |
| 10 | 96901618 |
| 11 | 810143038 |
| 12 | 6787465080 |
| 13 | 56871594099 |
| 14 | 473417649550 |
| 15 | 3913478050583 |
| 16 | 32192184170708 |
| 17 | 264014564271675 |
| 18 | 2158561440821352 |
| 19 | 17592866753339355 |
| 20 | 142983916007396542 |
| 21 | 1159269824603687631 |
| 22 | 9378694043134778568 |