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) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 23 |
| 5 | 57 |
| 6 | 141 |
| 7 | 351 |
| 8 | 875 |
| 9 | 2181 |
| 10 | 5435 |
| 11 | 13543 |
| 12 | 33747 |
| 13 | 84093 |
| 14 | 209549 |
| 15 | 522169 |
| 16 | 1301177 |
| 17 | 3242363 |
| 18 | 8079545 |
| 19 | 20133171 |
| 20 | 50169233 |
| 21 | 125015177 |
| 22 | 311521495 |
| 23 | 776270883 |
| 24 | 1934365665 |
| 25 | 4820186623 |
| 26 | 12011275583 |
| 27 | 29930530167 |
| 28 | 74582972465 |
| 29 | 185851027385 |