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 | 3 |
| 2 | 21 |
| 3 | 204 |
| 4 | 2130 |
| 5 | 22245 |
| 6 | 229119 |
| 7 | 2325966 |
| 8 | 23319708 |
| 9 | 231384327 |
| 10 | 2276119977 |
| 11 | 22228324368 |
| 12 | 215745006246 |
| 13 | 2082918495849 |
| 14 | 20017195390995 |
| 15 | 191593142789010 |
| 16 | 1827283815276144 |
| 17 | 17372064324294411 |
| 18 | 164687169445632573 |
| 19 | 1557231841690641492 |
| 20 | 14690512431146615802 |