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 | 5 |
| 4 | 15 |
| 5 | 52 |
| 6 | 203 |
| 7 | 877 |
| 8 | 4140 |
| 9 | 21147 |
| 10 | 115974 |
| 11 | 678559 |
| 12 | 4213465 |
| 13 | 27643007 |
| 14 | 190884307 |
| 15 | 1382802389 |
| 16 | 10478516523 |
| 17 | 82847813908 |
| 18 | 681895648039 |
| 19 | 5830788687491 |
| 20 | 51702731250650 |
| 21 | 474630475600569 |
| 22 | 4503991075480297 |
| 23 | 44120379612630694 |
| 24 | 445584481578266277 |
| 25 | 4634070027874688433 |