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 | 40 |
| 4 | 341 |
| 5 | 3906 |
| 6 | 55987 |
| 7 | 960800 |
| 8 | 19173961 |
| 9 | 435848050 |
| 10 | 11111111111 |
| 11 | 313842837672 |
| 12 | 9726655034461 |
| 13 | 328114698808274 |
| 14 | 11966776581370171 |
| 15 | 469172025408063616 |
| 16 | 19676527011956855057 |
| 17 | 878942778254232811938 |
| 18 | 41660902667961039785743 |
| 19 | 2088331858752553232964200 |