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 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 8 |
| 5 | 14 |
| 6 | 15 |
| 7 | -30 |
| 8 | -297 |
| 9 | -1442 |
| 10 | -5693 |
| 11 | -20046 |
| 12 | -64765 |
| 13 | -192911 |
| 14 | -522954 |
| 15 | -1236717 |
| 16 | -2221422 |
| 17 | -848673 |
| 18 | 18142403 |
| 19 | 122417208 |
| 20 | 573446212 |
| 21 | 2287694033 |
| 22 | 8211900486 |
| 23 | 26984131280 |
| 24 | 81027339912 |
| 25 | 217474121511 |
| 26 | 487508197964 |
| 27 | 690838844798 |
| 28 | -1034716617740 |