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) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 6 |
| 5 | 21 |
| 6 | 78 |
| 7 | 297 |
| 8 | 1143 |
| 9 | 4419 |
| 10 | 17118 |
| 11 | 66366 |
| 12 | 257391 |
| 13 | 998406 |
| 14 | 3873015 |
| 15 | 15024609 |
| 16 | 58285737 |
| 17 | 226111986 |
| 18 | 877174110 |
| 19 | 3402893997 |
| 20 | 13201132950 |
| 21 | 51212274057 |
| 22 | 198672129783 |
| 23 | 770725711035 |
| 24 | 2989941920334 |
| 25 | 11599136512038 |
| 26 | 44997518922327 |
| 27 | 174562710686622 |