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 | 1 |
| 3 | 1 |
| 4 | 4 |
| 5 | 18 |
| 6 | 93 |
| 7 | 579 |
| 8 | 4165 |
| 9 | 34031 |
| 10 | 311528 |
| 11 | 3158978 |
| 12 | 35154907 |
| 13 | 426029455 |
| 14 | 5585287179 |
| 15 | 78767551059 |
| 16 | 1189090451364 |
| 17 | 19133023344034 |
| 18 | 326894939779865 |
| 19 | 5910529926220115 |
| 20 | 112753567098061553 |
| 21 | 2263304875358959543 |
| 22 | 47687055915645538384 |
| 23 | 1052290471481700378570 |