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 | 0 |
| 1 | 1 |
| 2 | 4 |
| 3 | 14 |
| 4 | 56 |
| 5 | 256 |
| 6 | 1324 |
| 7 | 7664 |
| 8 | 49136 |
| 9 | 345856 |
| 10 | 2652244 |
| 11 | 22014464 |
| 12 | 196658216 |
| 13 | 1881389056 |
| 14 | 19192151164 |
| 15 | 207961585664 |
| 16 | 2385488163296 |
| 17 | 28879019769856 |
| 18 | 367966308562084 |
| 19 | 4922409168011264 |
| 20 | 68978503204900376 |
| 21 | 1010472388453728256 |
| 22 | 15445185289163949004 |