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 | 33 |
| 3 | 136 |
| 4 | 1121 |
| 5 | 4620 |
| 6 | 38081 |
| 7 | 156944 |
| 8 | 1293633 |
| 9 | 5331476 |
| 10 | 43945441 |
| 11 | 181113240 |
| 12 | 1492851361 |
| 13 | 6152518684 |
| 14 | 50713000833 |
| 15 | 209004522016 |
| 16 | 1722749176961 |
| 17 | 7100001229860 |
| 18 | 58522759015841 |
| 19 | 241191037293224 |