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 | 2 |
| 2 | 4 |
| 3 | 13 |
| 4 | 53 |
| 5 | 209 |
| 6 | 904 |
| 7 | 3963 |
| 8 | 17900 |
| 9 | 81745 |
| 10 | 378554 |
| 11 | 1768236 |
| 12 | 8327789 |
| 13 | 39471091 |
| 14 | 188145066 |
| 15 | 901117082 |
| 16 | 4334151970 |
| 17 | 20923370406 |
| 18 | 101341800704 |
| 19 | 492289834345 |