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 | 3 |
| 3 | 7 |
| 4 | 19 |
| 5 | 53 |
| 6 | 153 |
| 7 | 451 |
| 8 | 1339 |
| 9 | 3997 |
| 10 | 11961 |
| 11 | 35835 |
| 12 | 107435 |
| 13 | 322197 |
| 14 | 966425 |
| 15 | 2899027 |
| 16 | 8696699 |
| 17 | 26089517 |
| 18 | 78267673 |
| 19 | 234801675 |
| 20 | 704402987 |
| 21 | 2113205861 |
| 22 | 6339612857 |
| 23 | 19018831395 |
| 24 | 57056483259 |
| 25 | 171169433149 |
| 26 | 513508274169 |
| 27 | 1540524784027 |
| 28 | 4621574293547 |
| 29 | 13864722791605 |
| 30 | 41594168239321 |