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) |
|---|---|
| 1 | 0 |
| 2 | 2 |
| 3 | 7 |
| 4 | 16 |
| 5 | 60 |
| 6 | 272 |
| 7 | 1072 |
| 8 | 4096 |
| 9 | 16320 |
| 10 | 65792 |
| 11 | 262912 |
| 12 | 1048576 |
| 13 | 4193280 |
| 14 | 16781312 |
| 15 | 67121152 |
| 16 | 268435456 |
| 17 | 1073725440 |
| 18 | 4295032832 |
| 19 | 17180065792 |
| 20 | 68719476736 |
| 21 | 274877644800 |
| 22 | 1099512676352 |
| 23 | 4398049656832 |
| 24 | 17592186044416 |
| 25 | 70368739983360 |
| 26 | 281474993487872 |
| 27 | 1125899957174272 |
| 28 | 4503599627370496 |
| 29 | 18014398442373120 |