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 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 7 |
| 6 | 30 |
| 7 | 109 |
| 8 | 365 |
| 9 | 1164 |
| 10 | 3593 |
| 11 | 10835 |
| 12 | 32106 |
| 13 | 93845 |
| 14 | 271321 |
| 15 | 777432 |
| 16 | 2211025 |
| 17 | 6248479 |
| 18 | 17562870 |
| 19 | 49132669 |
| 20 | 136884293 |
| 21 | 379975140 |
| 22 | 1051356761 |
| 23 | 2900587115 |
| 24 | 7981564866 |
| 25 | 21911096357 |
| 26 | 60021530545 |
| 27 | 164095925424 |
| 28 | 447823729825 |
| 29 | 1220105286199 |
| 30 | 3319124711118 |