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 | 9 |
| 3 | 69 |
| 4 | 565 |
| 5 | 5305 |
| 6 | 56929 |
| 7 | 680685 |
| 8 | 8902349 |
| 9 | 126121313 |
| 10 | 1923133433 |
| 11 | 31379181461 |
| 12 | 544931376229 |
| 13 | 10024917092105 |
| 14 | 194602995875985 |
| 15 | 3972686705253181 |
| 16 | 85035210652191485 |
| 17 | 1903471938128641457 |
| 18 | 44453001710603619369 |
| 19 | 1080789854059236415973 |
| 20 | 27304602412815047204501 |