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 | 4 |
| 2 | 54 |
| 3 | 420 |
| 4 | 3088 |
| 5 | 25226 |
| 6 | 239994 |
| 7 | 2338286 |
| 8 | 23240168 |
| 9 | 232006814 |
| 10 | 2352889414 |
| 11 | 24069853302 |
| 12 | 248560741574 |
| 13 | 2582277394354 |
| 14 | 26997628173380 |
| 15 | 283652378887212 |
| 16 | 2994183763030920 |
| 17 | 31727834772912212 |
| 18 | 337396544704648686 |