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 | 2 |
| 3 | 5 |
| 4 | 14 |
| 5 | 39 |
| 6 | 109 |
| 7 | 312 |
| 8 | 890 |
| 9 | 2552 |
| 10 | 7325 |
| 11 | 21047 |
| 12 | 60465 |
| 13 | 173750 |
| 14 | 499068 |
| 15 | 1433071 |
| 16 | 4113105 |
| 17 | 11799780 |
| 18 | 33834367 |
| 19 | 96968462 |
| 20 | 277771344 |
| 21 | 795310628 |
| 22 | 2276055442 |
| 23 | 6510786627 |
| 24 | 18616389094 |
| 25 | 53207964655 |
| 26 | 152014267327 |
| 27 | 434136228215 |