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 | 4 |
| 2 | 28 |
| 3 | 298 |
| 4 | 4240 |
| 5 | 75394 |
| 6 | 1608688 |
| 7 | 40045618 |
| 8 | 1139279680 |
| 9 | 36463487554 |
| 10 | 1296712045648 |
| 11 | 50724943433938 |
| 12 | 2164652356532320 |
| 13 | 100072984472662114 |
| 14 | 4982304066392196208 |
| 15 | 265770533884409878258 |
| 16 | 15122101633293034668160 |
| 17 | 914210942121577873619074 |
| 18 | 58519992421072004957876368 |
| 19 | 3954059527570115477197922578 |