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 | 4 |
| 2 | 16 |
| 3 | 62 |
| 4 | 232 |
| 5 | 842 |
| 6 | 2980 |
| 7 | 10334 |
| 8 | 35248 |
| 9 | 118610 |
| 10 | 394684 |
| 11 | 1301126 |
| 12 | 4255624 |
| 13 | 13825658 |
| 14 | 44657428 |
| 15 | 143521838 |
| 16 | 459230560 |
| 17 | 1463719586 |
| 18 | 4649308012 |
| 19 | 14722502870 |
| 20 | 46491507256 |
| 21 | 146447041994 |
| 22 | 460259735236 |
| 23 | 1443537130622 |