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 | 1 |
| 2 | 4 |
| 3 | 65 |
| 4 | 566 |
| 5 | 10912 |
| 6 | 164032 |
| 7 | 3237313 |
| 8 | 62253130 |
| 9 | 1314421886 |
| 10 | 28392213224 |
| 11 | 639799858304 |
| 12 | 14785604868256 |
| 13 | 350615631856960 |
| 14 | 8485316740880384 |
| 15 | 209179475361783233 |
| 16 | 5239271305444731698 |
| 17 | 133100429387161703962 |
| 18 | 3424142506153260211720 |
| 19 | 89090362800169426107070 |