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 | 3 |
| 2 | 12 |
| 3 | 44 |
| 4 | 171 |
| 5 | 664 |
| 6 | 2688 |
| 7 | 11133 |
| 8 | 47682 |
| 9 | 210275 |
| 10 | 955940 |
| 11 | 4473128 |
| 12 | 21532160 |
| 13 | 106504216 |
| 14 | 540824997 |
| 15 | 2816636171 |
| 16 | 15031261538 |
| 17 | 82123830645 |
| 18 | 458979942506 |
| 19 | 2621982351176 |
| 20 | 15298840540234 |
| 21 | 91112889589166 |
| 22 | 553492059017778 |
| 23 | 3427579611162937 |
| 24 | 21625096669854023 |
| 25 | 138927108066308515 |