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 | 1 |
| 3 | 5 |
| 4 | 9 |
| 5 | 25 |
| 6 | 57 |
| 7 | 141 |
| 8 | 337 |
| 9 | 817 |
| 10 | 1969 |
| 11 | 4757 |
| 12 | 11481 |
| 13 | 27721 |
| 14 | 66921 |
| 15 | 161565 |
| 16 | 390049 |
| 17 | 941665 |
| 18 | 2273377 |
| 19 | 5488421 |
| 20 | 13250217 |
| 21 | 31988857 |
| 22 | 77227929 |
| 23 | 186444717 |
| 24 | 450117361 |
| 25 | 1086679441 |
| 26 | 2623476241 |
| 27 | 6333631925 |
| 28 | 15290740089 |
| 29 | 36915112105 |
| 30 | 89120964297 |