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 | 3 |
| 2 | 12 |
| 3 | 57 |
| 4 | 312 |
| 5 | 1923 |
| 6 | 13152 |
| 7 | 98697 |
| 8 | 805632 |
| 9 | 7102563 |
| 10 | 67233792 |
| 11 | 679970937 |
| 12 | 7315786752 |
| 13 | 83421156003 |
| 14 | 1004860895232 |
| 15 | 12749105088777 |
| 16 | 169926064668672 |
| 17 | 2373678328434243 |
| 18 | 34676591077097472 |
| 19 | 528758667342524217 |
| 20 | 8400613520498491392 |
| 21 | 138830752520282729283 |