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 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 19 |
| 5 | 76 |
| 6 | 271 |
| 7 | 904 |
| 8 | 2899 |
| 9 | 9076 |
| 10 | 27991 |
| 11 | 85504 |
| 12 | 259579 |
| 13 | 784876 |
| 14 | 2366911 |
| 15 | 7125304 |
| 16 | 21425059 |
| 17 | 64373476 |
| 18 | 193317031 |
| 19 | 580344304 |
| 20 | 1741819339 |
| 21 | 5227030876 |
| 22 | 15684238351 |
| 23 | 47059006504 |
| 24 | 141189602419 |
| 25 | 423593973076 |
| 26 | 1270832250871 |
| 27 | 3812597415904 |
| 28 | 11437993574299 |