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 | 3 |
| 4 | 7 |
| 5 | 43 |
| 6 | 148 |
| 7 | 1344 |
| 8 | 6171 |
| 9 | 74211 |
| 10 | 425976 |
| 11 | 6384708 |
| 12 | 43979902 |
| 13 | 789649750 |
| 14 | 6346283560 |
| 15 | 132789007200 |
| 16 | 1219725741715 |
| 17 | 29145283614115 |
| 18 | 301190499710320 |
| 19 | 8092186932120060 |
| 20 | 92921064554444490 |
| 21 | 2772830282722806978 |
| 22 | 35025128774218944648 |
| 23 | 1149343084932146388144 |