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 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 6 |
| 6 | 13 |
| 7 | 57 |
| 8 | 169 |
| 9 | 673 |
| 10 | 2301 |
| 11 | 8933 |
| 12 | 32747 |
| 13 | 127063 |
| 14 | 483484 |
| 15 | 1889957 |
| 16 | 7352241 |
| 17 | 29003446 |
| 18 | 114481435 |
| 19 | 455542880 |
| 20 | 1816976042 |
| 21 | 7285391071 |
| 22 | 29291855748 |
| 23 | 118218771203 |
| 24 | 478372112363 |
| 25 | 1941436590561 |
| 26 | 7897802784418 |
| 27 | 32205683248225 |
| 28 | 131602039333873 |