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 | 4 |
| 2 | 12 |
| 3 | 34 |
| 4 | 90 |
| 5 | 222 |
| 6 | 542 |
| 7 | 1302 |
| 8 | 3058 |
| 9 | 7186 |
| 10 | 16714 |
| 11 | 38670 |
| 12 | 89358 |
| 13 | 205710 |
| 14 | 472906 |
| 15 | 1086138 |
| 16 | 2491666 |
| 17 | 5713318 |
| 18 | 13094950 |
| 19 | 30003190 |
| 20 | 68731010 |
| 21 | 157423986 |
| 22 | 360530346 |
| 23 | 825626942 |
| 24 | 1890615518 |
| 25 | 4329196974 |
| 26 | 9912914314 |
| 27 | 22698017834 |
| 28 | 51972012258 |
| 29 | 119000208806 |