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 | 2 |
| 2 | 1 |
| 3 | 1 |
| 4 | -1 |
| 5 | 3 |
| 6 | -9 |
| 7 | 23 |
| 8 | -53 |
| 9 | 115 |
| 10 | -237 |
| 11 | 457 |
| 12 | -801 |
| 13 | 1213 |
| 14 | -1389 |
| 15 | 445 |
| 16 | 3667 |
| 17 | -15081 |
| 18 | 41335 |
| 19 | -95059 |
| 20 | 195769 |
| 21 | -370803 |
| 22 | 652463 |
| 23 | -1063359 |
| 24 | 1570205 |
| 25 | -1961755 |
| 26 | 1560269 |
| 27 | 1401991 |
| 28 | -11023119 |
| 29 | 36000427 |
| 30 | -93408425 |
| 31 | 214275735 |
| 32 | -450374071 |
| 33 | 879254493 |
| 34 | -1599245737 |
| 35 | 2695465017 |