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 | 1 |
| 3 | 0 |
| 4 | 3 |
| 5 | 1 |
| 6 | 18 |
| 7 | 13 |
| 8 | 155 |
| 9 | 168 |
| 10 | 1691 |
| 11 | 2381 |
| 12 | 22022 |
| 13 | 37401 |
| 14 | 331087 |
| 15 | 649036 |
| 16 | 5626103 |
| 17 | 12372161 |
| 18 | 106486594 |
| 19 | 257573405 |
| 20 | 2220690451 |
| 21 | 5824952232 |
| 22 | 50593271507 |
| 23 | 142387607469 |
| 24 | 1250521775454 |
| 25 | 3745193283657 |
| 26 | 33338037080183 |
| 27 | 105558942751948 |
| 28 | 953776675614223 |