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 | 6 |
| 3 | 52 |
| 4 | 602 |
| 5 | 8223 |
| 6 | 128917 |
| 7 | 2273716 |
| 8 | 44509914 |
| 9 | 957408649 |
| 10 | 22449011336 |
| 11 | 570032756328 |
| 12 | 15587503694363 |
| 13 | 456793916757139 |
| 14 | 14284890417759141 |
| 15 | 474896318288651220 |
| 16 | 16726743380843538668 |
| 17 | 622282429409944248297 |
| 18 | 24385251974172090147514 |
| 19 | 1004017088910699487855180 |