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 | 0 |
| 1 | 1 |
| 2 | 7 |
| 3 | 64 |
| 4 | 567 |
| 5 | 5041 |
| 6 | 44800 |
| 7 | 398161 |
| 8 | 3538647 |
| 9 | 31449664 |
| 10 | 279508327 |
| 11 | 2484125281 |
| 12 | 22077619200 |
| 13 | 196214447521 |
| 14 | 1743852408487 |
| 15 | 15498457228864 |
| 16 | 137742262651287 |
| 17 | 1224181906632721 |
| 18 | 10879894897043200 |
| 19 | 96694872166756081 |