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 | 4 |
| 3 | 18 |
| 4 | 121 |
| 5 | 1055 |
| 6 | 11376 |
| 7 | 145852 |
| 8 | 2165689 |
| 9 | 36532197 |
| 10 | 689873284 |
| 11 | 14415662558 |
| 12 | 330204013569 |
| 13 | 8226714806323 |
| 14 | 221470234531456 |
| 15 | 6406397898751320 |
| 16 | 198160750081637521 |
| 17 | 6526636388676159977 |
| 18 | 228040136335670652324 |