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 | 6 |
| 4 | 39 |
| 5 | 482 |
| 6 | 7053 |
| 7 | 117399 |
| 8 | 2070289 |
| 9 | 38097139 |
| 10 | 723169329 |
| 11 | 14074851642 |
| 12 | 279609377638 |
| 13 | 5651139037570 |
| 14 | 115901006038377 |
| 15 | 2407291353219949 |
| 16 | 50553753543016719 |
| 17 | 1071971262516091572 |
| 18 | 22926544048209731554 |
| 19 | 494103705426160765546 |
| 20 | 10722146465907412669810 |