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 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 27 |
| 6 | 78 |
| 7 | 234 |
| 8 | 722 |
| 9 | 2274 |
| 10 | 7280 |
| 11 | 23617 |
| 12 | 77466 |
| 13 | 256481 |
| 14 | 856016 |
| 15 | 2876940 |
| 16 | 9728090 |
| 17 | 33072228 |
| 18 | 112974592 |
| 19 | 387580856 |
| 20 | 1334821448 |
| 21 | 4613225722 |
| 22 | 15994465796 |
| 23 | 55615889745 |
| 24 | 193904367362 |
| 25 | 677709772035 |
| 26 | 2374027931492 |
| 27 | 8333765738127 |