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 | 2 |
| 3 | 6 |
| 4 | 20 |
| 5 | 62 |
| 6 | 172 |
| 7 | 471 |
| 8 | 1337 |
| 9 | 3846 |
| 10 | 11030 |
| 11 | 31442 |
| 12 | 89470 |
| 13 | 254934 |
| 14 | 727203 |
| 15 | 2074435 |
| 16 | 5915652 |
| 17 | 16866988 |
| 18 | 48093810 |
| 19 | 137141828 |
| 20 | 391072846 |
| 21 | 1115164897 |
| 22 | 3179915535 |
| 23 | 9067592160 |
| 24 | 25856510664 |
| 25 | 73730732368 |
| 26 | 210245631360 |
| 27 | 599521974384 |
| 28 | 1709555338705 |
| 29 | 4874850377793 |
| 30 | 13900789573274 |
| 31 | 39638539791222 |