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 | 0 |
| 1 | 3 |
| 2 | 11 |
| 3 | 47 |
| 4 | 210 |
| 5 | 985 |
| 6 | 4821 |
| 7 | 24427 |
| 8 | 126726 |
| 9 | 669432 |
| 10 | 3588148 |
| 11 | 19453038 |
| 12 | 106460872 |
| 13 | 587176205 |
| 14 | 3259873268 |
| 15 | 18200088376 |
| 16 | 102107048666 |
| 17 | 575281018454 |
| 18 | 3253321522134 |
| 19 | 18459252891532 |
| 20 | 105048100696856 |
| 21 | 599403542263094 |
| 22 | 3428437672359713 |
| 23 | 19652744592040804 |
| 24 | 112879982373565581 |
| 25 | 649538196329702877 |
| 26 | 3743885544339750283 |
| 27 | 21612949469350359942 |
| 28 | 124947894360104092955 |