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 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 25 |
| 5 | 114 |
| 6 | 591 |
| 7 | 3297 |
| 8 | 19528 |
| 9 | 120670 |
| 10 | 771276 |
| 11 | 5061164 |
| 12 | 33940023 |
| 13 | 231727313 |
| 14 | 1606423838 |
| 15 | 11282801628 |
| 16 | 80149508517 |
| 17 | 575046400808 |
| 18 | 4162193219619 |
| 19 | 30362723745089 |
| 20 | 223051844463559 |
| 21 | 1648987263156225 |
| 22 | 12260761096966077 |
| 23 | 91639607518612228 |
| 24 | 688209161117787657 |
| 25 | 5191094043137862845 |