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 | 78 |
| 2 | 2430 |
| 3 | 43758 |
| 4 | 537966 |
| 5 | 4969107 |
| 6 | 36685506 |
| 7 | 225961450 |
| 8 | 1198006524 |
| 9 | 5597569328 |
| 10 | 23474156784 |
| 11 | 89644484592 |
| 12 | 315415779120 |
| 13 | 1032380107812 |
| 14 | 3168537039954 |
| 15 | 9180278955210 |
| 16 | 25252641533405 |
| 17 | 66272502260250 |
| 18 | 166635797864250 |
| 19 | 402908157902250 |
| 20 | 939815697512250 |