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 | 4 |
| 2 | 40 |
| 3 | 612 |
| 4 | 11976 |
| 5 | 276836 |
| 6 | 7336248 |
| 7 | 219610532 |
| 8 | 7331824360 |
| 9 | 269576919908 |
| 10 | 10796426089880 |
| 11 | 466904884431268 |
| 12 | 21658080409800264 |
| 13 | 1071807203930733668 |
| 14 | 56328256034260866296 |
| 15 | 3131089417758323092388 |