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) |
|---|---|
| 4 | 1 |
| 5 | 0 |
| 6 | 0 |
| 7 | 0 |
| 8 | 14 |
| 9 | 42 |
| 10 | 90 |
| 11 | 165 |
| 12 | 737 |
| 13 | 3003 |
| 14 | 15652 |
| 15 | 55965 |
| 16 | 236924 |
| 17 | 851224 |
| 18 | 3872838 |
| 19 | 16766607 |
| 20 | 83026979 |
| 21 | 390791373 |
| 22 | 1941965432 |
| 23 | 9380708953 |
| 24 | 47629991554 |
| 25 | 241035098010 |
| 26 | 1284641489560 |
| 27 | 6852122431245 |
| 28 | 38078198632749 |
| 29 | 211138699725567 |
| 30 | 1208307893511470 |
| 31 | 6916339675763595 |