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 | 3 |
| 3 | 12 |
| 4 | 51 |
| 5 | 227 |
| 6 | 1052 |
| 7 | 5030 |
| 8 | 24634 |
| 9 | 122950 |
| 10 | 623140 |
| 11 | 3198502 |
| 12 | 16593124 |
| 13 | 86864578 |
| 14 | 458294970 |
| 15 | 2434421685 |
| 16 | 13008748377 |
| 17 | 69882215729 |
| 18 | 377172620330 |
| 19 | 2044303447067 |
| 20 | 11122504636031 |
| 21 | 60723579401396 |
| 22 | 332564474286299 |
| 23 | 1826591420755058 |
| 24 | 10058928726906713 |
| 25 | 55528582177881182 |
| 26 | 307224615377125853 |
| 27 | 1703330011411361882 |
| 28 | 9461963582991098963 |
| 29 | 52655804456941167376 |
| 30 | 293523046295844013225 |