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 | 3 |
| 3 | 7 |
| 4 | 10 |
| 5 | 24 |
| 6 | 186 |
| 7 | 492 |
| 8 | -1863 |
| 9 | -5240 |
| 10 | 79369 |
| 11 | 220350 |
| 12 | -2492912 |
| 13 | -6984296 |
| 14 | 90693060 |
| 15 | 254955852 |
| 16 | -3412605726 |
| 17 | -9625060440 |
| 18 | 133881917577 |
| 19 | 378533393025 |
| 20 | -5412043255536 |
| 21 | -15332556581976 |
| 22 | 224289105628470 |
| 23 | 636469447338144 |
| 24 | -9487486533101850 |
| 25 | -26960087538403992 |
| 26 | 408305313050817591 |
| 27 | 1161625141535962012 |
| 28 | -17832202665017550896 |
| 29 | -50783861201670203640 |
| 30 | 788741951929695672520 |