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 | 3 |
| 2 | 6 |
| 3 | 12 |
| 4 | 25 |
| 5 | 54 |
| 6 | 117 |
| 7 | 252 |
| 8 | 542 |
| 9 | 1167 |
| 10 | 2514 |
| 11 | 5415 |
| 12 | 11662 |
| 13 | 25116 |
| 14 | 54093 |
| 15 | 116502 |
| 16 | 250913 |
| 17 | 540396 |
| 18 | 1163862 |
| 19 | 2506635 |
| 20 | 5398594 |
| 21 | 11627067 |
| 22 | 25041462 |
| 23 | 53932332 |
| 24 | 116155217 |
| 25 | 250165974 |
| 26 | 538787805 |
| 27 | 1160398812 |
| 28 | 2499175726 |
| 29 | 5382528183 |