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) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 9 |
| 4 | 82 |
| 5 | 1300 |
| 6 | 15626 |
| 7 | 376761 |
| 8 | 6161988 |
| 9 | 176787117 |
| 10 | 3769318700 |
| 11 | 142364319625 |
| 12 | 3152513804548 |
| 13 | 154718778284148 |
| 14 | 4340009120036086 |
| 15 | 210971169748692000 |
| 16 | 7281661100510001416 |
| 17 | 435659030617933827136 |
| 18 | 14181101408561469791694 |
| 19 | 1052864393300587929716721 |
| 20 | 41673894815421072916530408 |