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) |
|---|---|
| 2 | 1 |
| 3 | 3 |
| 4 | 11 |
| 5 | 45 |
| 6 | 198 |
| 7 | 919 |
| 8 | 4446 |
| 9 | 22239 |
| 10 | 114347 |
| 11 | 601722 |
| 12 | 3229614 |
| 13 | 17632437 |
| 14 | 97707195 |
| 15 | 548538588 |
| 16 | 3115293151 |
| 17 | 17875151109 |
| 18 | 103511938302 |
| 19 | 604392787819 |
| 20 | 3555410248782 |
| 21 | 21057224371290 |
| 22 | 125484804821226 |
| 23 | 752020468811244 |
| 24 | 4530163818778839 |
| 25 | 27419805899781843 |
| 26 | 166694596163875206 |