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 | 2 |
| 2 | 18 |
| 3 | 218 |
| 4 | 2466 |
| 5 | 26282 |
| 6 | 269298 |
| 7 | 2685818 |
| 8 | 26269506 |
| 9 | 253202762 |
| 10 | 2413042578 |
| 11 | 22791125018 |
| 12 | 213710059746 |
| 13 | 1992110014442 |
| 14 | 18478745943858 |
| 15 | 170706760005818 |
| 16 | 1571545212141186 |
| 17 | 14425381885981322 |
| 18 | 132080236787517138 |
| 19 | 1206736529597136218 |
| 20 | 11004743954450081826 |
| 21 | 100195617094657583402 |