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 | 0 |
| 2 | 21 |
| 3 | 0 |
| 4 | 381 |
| 5 | 136 |
| 6 | 5189 |
| 7 | 544 |
| 8 | 94493 |
| 9 | 43176 |
| 10 | 1311749 |
| 11 | 254944 |
| 12 | 24400989 |
| 13 | 10617384 |
| 14 | 336720133 |
| 15 | 59386080 |
| 16 | 6262162781 |
| 17 | 2688081960 |
| 18 | 86425034501 |
| 19 | 15602819808 |
| 20 | 1602324730205 |
| 21 | 689510189096 |
| 22 | 22111597905669 |
| 23 | 4029655427808 |
| 24 | 410123492458845 |
| 25 | 176987155003432 |
| 26 | 5661487452198661 |
| 27 | 1029729726008032 |
| 28 | 104994856690270557 |
| 29 | 45284638610044968 |