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 | 1 |
| 3 | 4 |
| 4 | 29 |
| 5 | 311 |
| 6 | 4447 |
| 7 | 79745 |
| 8 | 1722681 |
| 9 | 43578820 |
| 10 | 1264185051 |
| 11 | 41381702275 |
| 12 | 1509114454597 |
| 13 | 60681141052273 |
| 14 | 2667370764248023 |
| 15 | 127258109992533616 |
| 16 | 6549338612837162225 |
| 17 | 361680134713529977507 |
| 18 | 21333858798449021030515 |
| 19 | 1338681172839439064846881 |