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) |
|---|---|
| 1 | 1 |
| 2 | 20 |
| 3 | 109 |
| 4 | 841 |
| 5 | 5680 |
| 6 | 40065 |
| 7 | 278105 |
| 8 | 1940868 |
| 9 | 13518605 |
| 10 | 94223329 |
| 11 | 656569824 |
| 12 | 4575509121 |
| 13 | 31884910129 |
| 14 | 222195588532 |
| 15 | 1548403370477 |
| 16 | 10790295445561 |
| 17 | 75193858910224 |
| 18 | 524000231073025 |
| 19 | 3651577819301001 |
| 20 | 25446593414689700 |