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 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 6 |
| 6 | 17 |
| 7 | 43 |
| 8 | 135 |
| 9 | 536 |
| 10 | 2262 |
| 11 | 9109 |
| 12 | 40119 |
| 13 | 198069 |
| 14 | 1057149 |
| 15 | 5656915 |
| 16 | 31937212 |
| 17 | 191032078 |
| 18 | 1218669125 |
| 19 | 7948119483 |
| 20 | 54117500635 |
| 21 | 381631039690 |
| 22 | 2828205076600 |
| 23 | 21507011811289 |
| 24 | 169880627954541 |
| 25 | 1377653319819302 |
| 26 | 11620433411120653 |
| 27 | 100417638302823210 |