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 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 3 |
| 6 | 11 |
| 7 | 59 |
| 8 | 369 |
| 9 | 2665 |
| 10 | 21823 |
| 11 | 199983 |
| 12 | 2028701 |
| 13 | 22577141 |
| 14 | 273551115 |
| 15 | 3585133147 |
| 16 | 50540288857 |
| 17 | 762641865009 |
| 18 | 12265883397719 |
| 19 | 209475278413895 |
| 20 | 3785852926650453 |
| 21 | 72191462591370733 |
| 22 | 1448516763956727331 |
| 23 | 30507960955933725171 |
| 24 | 672958104387944656145 |