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 | 9 |
| 2 | 34 |
| 3 | 125 |
| 4 | 462 |
| 5 | 1722 |
| 6 | 6468 |
| 7 | 24453 |
| 8 | 92950 |
| 9 | 354926 |
| 10 | 1360476 |
| 11 | 5231954 |
| 12 | 20177164 |
| 13 | 78004500 |
| 14 | 302211720 |
| 15 | 1173076245 |
| 16 | 4561139430 |
| 17 | 17761336230 |
| 18 | 69257611500 |
| 19 | 270391268070 |
| 20 | 1056823387620 |