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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 1 |
| 6 | 7 |
| 7 | 9 |
| 8 | 37 |
| 9 | 79 |
| 10 | 273 |
| 11 | 755 |
| 12 | 2648 |
| 13 | 8432 |
| 14 | 29872 |
| 15 | 104624 |
| 16 | 384759 |
| 17 | 1432655 |
| 18 | 5502563 |
| 19 | 21533141 |
| 20 | 86291313 |
| 21 | 352654980 |
| 22 | 1471073073 |
| 23 | 6253397866 |
| 24 | 27083003687 |
| 25 | 119399628021 |
| 26 | 535591458635 |
| 27 | 2443030798539 |
| 28 | 11326169401988 |
| 29 | 53343974825122 |
| 30 | 255121588496338 |