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 | 34 |
| 3 | 368 |
| 4 | 4495 |
| 5 | 59052 |
| 6 | 814506 |
| 7 | 11633440 |
| 8 | 170574723 |
| 9 | 2552698720 |
| 10 | 38832808586 |
| 11 | 598724403680 |
| 12 | 9335085772194 |
| 13 | 146936230074004 |
| 14 | 2331703871687400 |
| 15 | 37263447339612480 |
| 16 | 599206511767593099 |
| 17 | 9688121925389895636 |
| 18 | 157401957319775436400 |
| 19 | 2568427016865897264000 |