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 | 39 |
| 4 | 320 |
| 5 | 2787 |
| 6 | 25788 |
| 7 | 247731 |
| 8 | 2449188 |
| 9 | 24753960 |
| 10 | 254610962 |
| 11 | 2656496133 |
| 12 | 28046838948 |
| 13 | 299085697722 |
| 14 | 3216723340218 |
| 15 | 34852657892685 |
| 16 | 380063012970680 |
| 17 | 4168108473073596 |
| 18 | 45941874232280862 |
| 19 | 508664757809869052 |