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) |
|---|---|
| 4 | 1 |
| 5 | 11 |
| 6 | 231 |
| 7 | 3311 |
| 8 | 56287 |
| 9 | 875007 |
| 10 | 14208447 |
| 11 | 225683007 |
| 12 | 3624203583 |
| 13 | 57881286463 |
| 14 | 926949282623 |
| 15 | 14824402656063 |
| 16 | 237244744338239 |
| 17 | 3795481554332479 |
| 18 | 60731179948567359 |
| 19 | 971671079497526079 |
| 20 | 15546959673214593855 |