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 | 5 |
| 3 | 104 |
| 4 | 836 |
| 5 | 7315 |
| 6 | 202895 |
| 7 | 1949900 |
| 8 | 19284511 |
| 9 | 1754890501 |
| 10 | 18058389349 |
| 11 | 188502545504 |
| 12 | 5973492827120 |
| 13 | 63732573470888 |
| 14 | 685813307216632 |
| 15 | 22303841469480032 |
| 16 | 243350841747362492 |
| 17 | 2670252449037801100 |
| 18 | 265034693078133749180 |
| 19 | 2936064912067020698720 |