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 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 6 |
| 5 | 21 |
| 6 | 112 |
| 7 | 697 |
| 8 | 6386 |
| 9 | 75700 |
| 10 | 1156842 |
| 11 | 21503340 |
| 12 | 471142472 |
| 13 | 11851753163 |
| 14 | 336605142326 |
| 15 | 10661879669294 |
| 16 | 373171677147769 |
| 17 | 14326039970010402 |
| 18 | 599529134063451455 |
| 19 | 27206654007549974712 |
| 20 | 1332697569146848014994 |
| 21 | 70181910345392508318643 |
| 22 | 3959059626001669328959513 |