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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 1 |
| 7 | 3 |
| 8 | 12 |
| 9 | 57 |
| 10 | 348 |
| 11 | 2460 |
| 12 | 19806 |
| 13 | 178950 |
| 14 | 1794420 |
| 15 | 19778210 |
| 16 | 237696420 |
| 17 | 3093642300 |
| 18 | 43350548655 |
| 19 | 650733622665 |
| 20 | 10417925247240 |
| 21 | 177191430300339 |
| 22 | 3190747212651432 |
| 23 | 60645032890871688 |
| 24 | 1213255040678034508 |
| 25 | 25484737348664027532 |
| 26 | 560785511736390349080 |