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 | 3 |
| 3 | 12 |
| 4 | 65 |
| 5 | 443 |
| 6 | 3626 |
| 7 | 34811 |
| 8 | 384479 |
| 9 | 4806098 |
| 10 | 67109281 |
| 11 | 1035627571 |
| 12 | 17505788792 |
| 13 | 321689532755 |
| 14 | 6385033369589 |
| 15 | 136124555962844 |
| 16 | 3102031758758001 |
| 17 | 75238874818446123 |
| 18 | 1935053096953675800 |
| 19 | 52595740530868430967 |
| 20 | 1506344153813275882667 |