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 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 13 |
| 5 | 41 |
| 6 | 461 |
| 7 | 2745 |
| 8 | 32397 |
| 9 | 288937 |
| 10 | 3794605 |
| 11 | 44758649 |
| 12 | 665371565 |
| 13 | 9660560937 |
| 14 | 162652002189 |
| 15 | 2782536864697 |
| 16 | 52737562595917 |
| 17 | 1033546861769513 |
| 18 | 21867683869860845 |
| 19 | 481630083492884601 |
| 20 | 11277805333488014445 |
| 21 | 275314710164399079337 |
| 22 | 7077059249870048306125 |