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 | 3 |
| 2 | 9 |
| 3 | 31 |
| 4 | 120 |
| 5 | 514 |
| 6 | 2407 |
| 7 | 12205 |
| 8 | 66491 |
| 9 | 386699 |
| 10 | 2388096 |
| 11 | 15589732 |
| 12 | 107165081 |
| 13 | 773106715 |
| 14 | 5836100685 |
| 15 | 45981026703 |
| 16 | 377230766908 |
| 17 | 3215977070706 |
| 18 | 28437411817135 |
| 19 | 260380616093533 |
| 20 | 2464930698184351 |
| 21 | 24091925888687459 |
| 22 | 242802079705721156 |
| 23 | 2520198597834860148 |