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 | 7 |
| 4 | 18 |
| 5 | 52 |
| 6 | 143 |
| 7 | 396 |
| 8 | 1083 |
| 9 | 2971 |
| 10 | 8087 |
| 11 | 21981 |
| 12 | 59533 |
| 13 | 160857 |
| 14 | 433467 |
| 15 | 1165542 |
| 16 | 3126951 |
| 17 | 8372451 |
| 18 | 22374172 |
| 19 | 59684669 |
| 20 | 158941356 |
| 21 | 422582925 |
| 22 | 1121814072 |
| 23 | 2973703449 |
| 24 | 7871754065 |
| 25 | 20809918535 |
| 26 | 54943916547 |
| 27 | 144891525408 |
| 28 | 381647503607 |
| 29 | 1004149670985 |