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 | 0 |
| 3 | 4 |
| 4 | 13 |
| 5 | 98 |
| 6 | 748 |
| 7 | 9982 |
| 8 | 205290 |
| 9 | 6546960 |
| 10 | 352371887 |
| 11 | 29668304472 |
| 12 | 4303531187466 |
| 13 | 985391751078694 |
| 14 | 391866509275972993 |
| 15 | 248491878411568471280 |
| 16 | 274544424465100159954078 |
| 17 | 488310442484985365942048784 |
| 18 | 1513516279388226593561422201905 |