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 | 4 |
| 1 | 9 |
| 2 | 49 |
| 3 | 324 |
| 4 | 2209 |
| 5 | 15129 |
| 6 | 103684 |
| 7 | 710649 |
| 8 | 4870849 |
| 9 | 33385284 |
| 10 | 228826129 |
| 11 | 1568397609 |
| 12 | 10749957124 |
| 13 | 73681302249 |
| 14 | 505019158609 |
| 15 | 3461452808004 |
| 16 | 23725150497409 |
| 17 | 162614600673849 |
| 18 | 1114577054219524 |
| 19 | 7639424778862809 |