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 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 0 |
| 8 | 0 |
| 9 | 0 |
| 10 | 4 |
| 11 | 44 |
| 12 | 156 |
| 13 | 1876 |
| 14 | 5180 |
| 15 | 32516 |
| 16 | 202900 |
| 17 | 1330622 |
| 18 | 8924976 |
| 19 | 64492432 |
| 20 | 495864256 |
| 21 | 3977841852 |
| 22 | 34092182276 |
| 23 | 306819842212 |
| 24 | 2883202816808 |
| 25 | 28144109776812 |
| 26 | 286022102245804 |