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 | 9 |
| 4 | 38 |
| 5 | 136 |
| 6 | 452 |
| 7 | 1495 |
| 8 | 5031 |
| 9 | 17114 |
| 10 | 58282 |
| 11 | 198032 |
| 12 | 671856 |
| 13 | 2278870 |
| 14 | 7731892 |
| 15 | 26238839 |
| 16 | 89047335 |
| 17 | 302191369 |
| 18 | 1025487338 |
| 19 | 3479970844 |
| 20 | 11809261583 |
| 21 | 40074827170 |
| 22 | 135994407483 |
| 23 | 461498426696 |
| 24 | 1566098800484 |
| 25 | 5314568565096 |
| 26 | 18035031128780 |
| 27 | 61202027710656 |