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 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 16 |
| 5 | 76 |
| 6 | 272 |
| 7 | 1008 |
| 8 | 4096 |
| 9 | 16576 |
| 10 | 65792 |
| 11 | 261888 |
| 12 | 1048576 |
| 13 | 4197376 |
| 14 | 16781312 |
| 15 | 67104768 |
| 16 | 268435456 |
| 17 | 1073790976 |
| 18 | 4295032832 |
| 19 | 17179803648 |
| 20 | 68719476736 |
| 21 | 274878693376 |
| 22 | 1099512676352 |
| 23 | 4398045462528 |
| 24 | 17592186044416 |
| 25 | 70368756760576 |
| 26 | 281474993487872 |
| 27 | 1125899890065408 |
| 28 | 4503599627370496 |
| 29 | 18014398710808576 |