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 | 3 |
| 2 | 16 |
| 3 | 129 |
| 4 | 1420 |
| 5 | 19881 |
| 6 | 337978 |
| 7 | 6759561 |
| 8 | 155469904 |
| 9 | 4042217505 |
| 10 | 117224307646 |
| 11 | 3751177844673 |
| 12 | 131291224563556 |
| 13 | 4989066533415129 |
| 14 | 204551727870020290 |
| 15 | 9000276026280892761 |
| 16 | 423012973235201959768 |
| 17 | 21150648661760097988401 |
| 18 | 1120984379073285193385254 |