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) |
|---|---|
| 3 | 0 |
| 4 | 4 |
| 5 | 45 |
| 6 | 251 |
| 7 | 1078 |
| 8 | 4054 |
| 9 | 14115 |
| 10 | 46837 |
| 11 | 150612 |
| 12 | 474200 |
| 13 | 1471561 |
| 14 | 4520959 |
| 15 | 13792002 |
| 16 | 41867242 |
| 17 | 126649983 |
| 18 | 382177817 |
| 19 | 1151251648 |
| 20 | 3463715980 |
| 21 | 10412118981 |
| 22 | 31280396611 |
| 23 | 93933463950 |
| 24 | 281993329214 |
| 25 | 846382640155 |
| 26 | 2539986780541 |
| 27 | 7621705171308 |
| 28 | 22868739391744 |
| 29 | 68613734367105 |
| 30 | 205856772356807 |