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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 5 |
| 6 | 22 |
| 7 | 84 |
| 8 | 314 |
| 9 | 1144 |
| 10 | 4143 |
| 11 | 14954 |
| 12 | 54020 |
| 13 | 195526 |
| 14 | 709927 |
| 15 | 2586629 |
| 16 | 9459464 |
| 17 | 34722823 |
| 18 | 127923631 |
| 19 | 472950024 |
| 20 | 1754436962 |
| 21 | 6528898588 |
| 22 | 24369211839 |
| 23 | 91214280785 |
| 24 | 342315888666 |
| 25 | 1287836972679 |
| 26 | 4856186764942 |
| 27 | 18351269337823 |
| 28 | 69488543849735 |