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 | 20 |
| 4 | 117 |
| 5 | 770 |
| 6 | 5581 |
| 7 | 44023 |
| 8 | 375118 |
| 9 | 3434312 |
| 10 | 33632306 |
| 11 | 350894959 |
| 12 | 3885892547 |
| 13 | 45520247052 |
| 14 | 562266198499 |
| 15 | 7301972285296 |
| 16 | 99436168734138 |
| 17 | 1416444089850373 |
| 18 | 21059162813775906 |
| 19 | 326127491494213657 |