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 | 2 |
| 2 | 7 |
| 3 | 37 |
| 4 | 266 |
| 5 | 2431 |
| 6 | 27007 |
| 7 | 353522 |
| 8 | 5329837 |
| 9 | 90960751 |
| 10 | 1733584106 |
| 11 | 36496226977 |
| 12 | 841146804577 |
| 13 | 21065166341402 |
| 14 | 569600638022431 |
| 15 | 16539483668991901 |
| 16 | 513293594376771362 |
| 17 | 16955228098102446847 |
| 18 | 593946277027962411007 |
| 19 | 21992967478132711654106 |
| 20 | 858319677924203716921141 |