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 | 5 |
| 2 | 21 |
| 3 | 86 |
| 4 | 349 |
| 5 | 1410 |
| 6 | 5682 |
| 7 | 22860 |
| 8 | 91869 |
| 9 | 368906 |
| 10 | 1480486 |
| 11 | 5938740 |
| 12 | 23813746 |
| 13 | 95462996 |
| 14 | 382594884 |
| 15 | 1533053976 |
| 16 | 6141910749 |
| 17 | 24603000666 |
| 18 | 98541647454 |
| 19 | 394644228516 |
| 20 | 1580344177254 |
| 21 | 6327940829436 |
| 22 | 25336229584764 |
| 23 | 101436400902696 |
| 24 | 406088663224434 |
| 25 | 1625644557045060 |
| 26 | 6507440174581692 |
| 27 | 26048128051398920 |