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 | 0 |
| 2 | 8 |
| 3 | 40 |
| 4 | 257 |
| 5 | 1534 |
| 6 | 9314 |
| 7 | 56314 |
| 8 | 341988 |
| 9 | 2082546 |
| 10 | 12729304 |
| 11 | 78083158 |
| 12 | 480688451 |
| 13 | 2969319278 |
| 14 | 18402445258 |
| 15 | 114405090020 |
| 16 | 713334999381 |
| 17 | 4460132045862 |
| 18 | 27960102769656 |
| 19 | 175711836643538 |
| 20 | 1106809365488500 |
| 21 | 6987092970919342 |