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 | 10 |
| 3 | 39 |
| 4 | 276 |
| 5 | 3155 |
| 6 | 46698 |
| 7 | 823599 |
| 8 | 16777288 |
| 9 | 387420579 |
| 10 | 10000000110 |
| 11 | 285311670743 |
| 12 | 8916100448412 |
| 13 | 302875106592435 |
| 14 | 11112006825558226 |
| 15 | 437893890380859615 |
| 16 | 18446744073709551888 |
| 17 | 827240261886336764483 |
| 18 | 39346408075296537575766 |
| 19 | 1978419655660313589124359 |