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 | 2 |
| 1 | 1 |
| 2 | 3 |
| 3 | 10 |
| 4 | 55 |
| 5 | 311 |
| 6 | 2446 |
| 7 | 19447 |
| 8 | 196337 |
| 9 | 2014777 |
| 10 | 24828706 |
| 11 | 311108051 |
| 12 | 4507990477 |
| 13 | 66719239237 |
| 14 | 1112079627842 |
| 15 | 18945126606421 |
| 16 | 356368711926481 |
| 17 | 6867187345103057 |
| 18 | 143985206958508162 |
| 19 | 3092256807348721807 |
| 20 | 71426909592196938101 |
| 21 | 1691486262041519369581 |