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 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 84 |
| 6 | 387 |
| 7 | 1953 |
| 8 | 10802 |
| 9 | 64267 |
| 10 | 408489 |
| 11 | 2750686 |
| 12 | 19518841 |
| 13 | 145236878 |
| 14 | 1128884559 |
| 15 | 9135566309 |
| 16 | 76758391212 |
| 17 | 667993213393 |
| 18 | 6008434514996 |
| 19 | 55755719348210 |
| 20 | 532896254763646 |
| 21 | 5238211003916685 |
| 22 | 52885470406233727 |
| 23 | 547751388283907208 |
| 24 | 5813693205313803535 |
| 25 | 63170000832869927871 |