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 | 7 |
| 2 | 53 |
| 3 | 318 |
| 4 | 1784 |
| 5 | 9288 |
| 6 | 46233 |
| 7 | 221859 |
| 8 | 1036585 |
| 9 | 4742650 |
| 10 | 21350264 |
| 11 | 94895016 |
| 12 | 417562385 |
| 13 | 1822824255 |
| 14 | 7907350365 |
| 15 | 34130697462 |
| 16 | 146735898760 |
| 17 | 628870859320 |
| 18 | 2688466352825 |
| 19 | 11470754475675 |
| 20 | 48865641344081 |
| 21 | 207913415718642 |