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 | 3 |
| 3 | 11 |
| 4 | 38 |
| 5 | 126 |
| 6 | 415 |
| 7 | 1369 |
| 8 | 4521 |
| 9 | 14933 |
| 10 | 49322 |
| 11 | 162900 |
| 12 | 538021 |
| 13 | 1776961 |
| 14 | 5868903 |
| 15 | 19383671 |
| 16 | 64019918 |
| 17 | 211443426 |
| 18 | 698350195 |
| 19 | 2306494009 |
| 20 | 7617832221 |
| 21 | 25159990673 |
| 22 | 83097804242 |
| 23 | 274453403400 |
| 24 | 906458014441 |
| 25 | 2993827446721 |
| 26 | 9887940354603 |
| 27 | 32657648510531 |