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) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 4 |
| 5 | 10 |
| 6 | 34 |
| 7 | 103 |
| 8 | 346 |
| 9 | 1153 |
| 10 | 3965 |
| 11 | 13746 |
| 12 | 48396 |
| 13 | 171835 |
| 14 | 615966 |
| 15 | 2223755 |
| 16 | 8082457 |
| 17 | 29543309 |
| 18 | 108545916 |
| 19 | 400623807 |
| 20 | 1484716135 |
| 21 | 5522723344 |
| 22 | 20612084010 |
| 23 | 77164686511 |
| 24 | 289688970195 |
| 25 | 1090342139349 |
| 26 | 4113620233260 |
| 27 | 15553877949800 |
| 28 | 58930127470164 |