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 | 4 |
| 4 | 10 |
| 5 | 31 |
| 6 | 110 |
| 7 | 421 |
| 8 | 1686 |
| 9 | 6961 |
| 10 | 29392 |
| 11 | 126292 |
| 12 | 550360 |
| 13 | 2426503 |
| 14 | 10803802 |
| 15 | 48507844 |
| 16 | 219377950 |
| 17 | 998436793 |
| 18 | 4569488372 |
| 19 | 21016589074 |
| 20 | 97090411020 |
| 21 | 450314942683 |
| 22 | 2096122733212 |
| 23 | 9788916220519 |
| 24 | 45850711498860 |
| 25 | 215348942668681 |
| 26 | 1013979873542690 |
| 27 | 4785437476592806 |