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 | 6 |
| 3 | 33 |
| 4 | 280 |
| 5 | 3145 |
| 6 | 46956 |
| 7 | 823585 |
| 8 | 16781472 |
| 9 | 387422001 |
| 10 | 10000100440 |
| 11 | 285311670721 |
| 12 | 8916103479504 |
| 13 | 302875106592409 |
| 14 | 11112006930972780 |
| 15 | 437893890382391745 |
| 16 | 18446744078004651136 |
| 17 | 827240261886336764449 |
| 18 | 39346408075494964903956 |
| 19 | 1978419655660313589124321 |