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 | 3 |
| 3 | 10 |
| 4 | 39 |
| 5 | 156 |
| 6 | 630 |
| 7 | 2556 |
| 8 | 10431 |
| 9 | 42823 |
| 10 | 176748 |
| 11 | 732810 |
| 12 | 3049722 |
| 13 | 12732188 |
| 14 | 53299284 |
| 15 | 223645200 |
| 16 | 940355391 |
| 17 | 3961092906 |
| 18 | 16712516565 |
| 19 | 70615352330 |
| 20 | 298761296064 |
| 21 | 1265504676810 |
| 22 | 5366250376710 |
| 23 | 22777466596560 |
| 24 | 96768003904650 |
| 25 | 411451657313931 |
| 26 | 1750809473690436 |
| 27 | 7455339422353396 |