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 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 10 |
| 4 | 28 |
| 5 | 126 |
| 6 | 236 |
| 7 | 1716 |
| 8 | 4376 |
| 9 | 24310 |
| 10 | 71452 |
| 11 | 352716 |
| 12 | 1036432 |
| 13 | 5200300 |
| 14 | 15661088 |
| 15 | 77558760 |
| 16 | 234338224 |
| 17 | 1166803110 |
| 18 | 3538500140 |
| 19 | 17672631900 |
| 20 | 53754680928 |
| 21 | 269128937220 |
| 22 | 811847006192 |
| 23 | 4116715363800 |
| 24 | 12392037943040 |
| 25 | 63205303218876 |
| 26 | 190668639444376 |