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 | 5 |
| 2 | 21 |
| 3 | 69 |
| 4 | 277 |
| 5 | 1349 |
| 6 | 5141 |
| 7 | 16453 |
| 8 | 65813 |
| 9 | 329029 |
| 10 | 1381397 |
| 11 | 4538437 |
| 12 | 18088213 |
| 13 | 88081733 |
| 14 | 335549461 |
| 15 | 1073758277 |
| 16 | 4295033109 |
| 17 | 21475165509 |
| 18 | 90195694613 |
| 19 | 296357281861 |
| 20 | 1189724029205 |
| 21 | 5793998964037 |
| 22 | 22080762418197 |
| 23 | 70666170679365 |