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 | 20 |
| 2 | 356 |
| 3 | 6096 |
| 4 | 102436 |
| 5 | 1702480 |
| 6 | 28093456 |
| 7 | 461273920 |
| 8 | 7546019620 |
| 9 | 123100218320 |
| 10 | 2003738272656 |
| 11 | 32557446669120 |
| 12 | 528231606378256 |
| 13 | 8559878182412096 |
| 14 | 138567392514153536 |
| 15 | 2241139725237406976 |
| 16 | 36219533239041063716 |
| 17 | 584958249814679707856 |
| 18 | 9441690077748181415696 |