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 | 109 |
| 4 | 1641 |
| 5 | 27151 |
| 6 | 478341 |
| 7 | 8782075 |
| 8 | 166237161 |
| 9 | 3220837534 |
| 10 | 63562741159 |
| 11 | 1273237637706 |
| 12 | 25820645555109 |
| 13 | 529080420540114 |
| 14 | 10937268142896643 |
| 15 | 227824992158991334 |
| 16 | 4777204094770874857 |
| 17 | 100757627271124231383 |
| 18 | 2136117417348870713646 |
| 19 | 45496022230420668679932 |