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 | 5 |
| 2 | 30 |
| 3 | 145 |
| 4 | 660 |
| 5 | 2777 |
| 6 | 11160 |
| 7 | 42805 |
| 8 | 158490 |
| 9 | 568050 |
| 10 | 1980607 |
| 11 | 6735380 |
| 12 | 22402610 |
| 13 | 73022755 |
| 14 | 233692345 |
| 15 | 735350970 |
| 16 | 2278153310 |
| 17 | 6956560935 |
| 18 | 20958613740 |
| 19 | 62354061740 |
| 20 | 183332498533 |
| 21 | 533074229590 |
| 22 | 1533842417185 |
| 23 | 4369816273820 |
| 24 | 12332669124455 |
| 25 | 34495668855729 |