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 | 39 |
| 4 | 147 |
| 5 | 498 |
| 6 | 1821 |
| 7 | 6303 |
| 8 | 22692 |
| 9 | 79419 |
| 10 | 283647 |
| 11 | 998418 |
| 12 | 3551241 |
| 13 | 12537003 |
| 14 | 44498172 |
| 15 | 157331199 |
| 16 | 557814747 |
| 17 | 1973795538 |
| 18 | 6994128261 |
| 19 | 24758288103 |
| 20 | 87705442452 |
| 21 | 310530035379 |
| 22 | 1099879017447 |
| 23 | 3894649335858 |
| 24 | 13793560492881 |
| 25 | 48845404515603 |
| 26 | 172987448951532 |