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 | 16 |
| 3 | 63 |
| 4 | 248 |
| 5 | 980 |
| 6 | 3894 |
| 7 | 15563 |
| 8 | 62555 |
| 9 | 252789 |
| 10 | 1026623 |
| 11 | 4188390 |
| 12 | 17159382 |
| 13 | 70570380 |
| 14 | 291253664 |
| 15 | 1205935204 |
| 16 | 5008047097 |
| 17 | 20854723702 |
| 18 | 87064706122 |
| 19 | 364334839028 |
| 20 | 1527943938306 |
| 21 | 6420911995109 |
| 22 | 27033938458595 |