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 | 21 |
| 1 | 65 |
| 2 | 325 |
| 3 | 1105 |
| 4 | 5397 |
| 5 | 16705 |
| 6 | 83013 |
| 7 | 283985 |
| 8 | 1376277 |
| 9 | 4259905 |
| 10 | 21299525 |
| 11 | 72418385 |
| 12 | 353703189 |
| 13 | 1094795585 |
| 14 | 5440291909 |
| 15 | 18611524945 |
| 16 | 90194313237 |
| 17 | 279172874305 |
| 18 | 1395864371525 |
| 19 | 4745938863185 |
| 20 | 23179938501909 |