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 | 0 |
| 1 | 1 |
| 2 | 4 |
| 3 | 13 |
| 4 | 40 |
| 5 | 117 |
| 6 | 332 |
| 7 | 921 |
| 8 | 2512 |
| 9 | 6761 |
| 10 | 18004 |
| 11 | 47525 |
| 12 | 124536 |
| 13 | 324317 |
| 14 | 840092 |
| 15 | 2166065 |
| 16 | 5562272 |
| 17 | 14232273 |
| 18 | 36300196 |
| 19 | 92321085 |
| 20 | 234192584 |
| 21 | 592695109 |
| 22 | 1496810732 |
| 23 | 3772761289 |
| 24 | 9492450672 |
| 25 | 23844342073 |
| 26 | 59804611060 |
| 27 | 149787196117 |