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 | 2 |
| 3 | 4 |
| 4 | 9 |
| 5 | 22 |
| 6 | 58 |
| 7 | 163 |
| 8 | 483 |
| 9 | 1494 |
| 10 | 4783 |
| 11 | 15740 |
| 12 | 52956 |
| 13 | 181391 |
| 14 | 630533 |
| 15 | 2218761 |
| 16 | 7888266 |
| 17 | 28291588 |
| 18 | 102237141 |
| 19 | 371884771 |
| 20 | 1360527143 |
| 21 | 5002837936 |
| 22 | 18479695171 |
| 23 | 68539149518 |
| 24 | 255137783916 |
| 25 | 952914971191 |
| 26 | 3569834343547 |
| 27 | 13410481705795 |