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 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 14 |
| 5 | 42 |
| 6 | 132 |
| 7 | 431 |
| 8 | 1452 |
| 9 | 5026 |
| 10 | 17808 |
| 11 | 64398 |
| 12 | 237097 |
| 13 | 886935 |
| 14 | 3365348 |
| 15 | 12933691 |
| 16 | 50285912 |
| 17 | 197586405 |
| 18 | 783922944 |
| 19 | 3138088910 |
| 20 | 12666148475 |
| 21 | 51517864816 |
| 22 | 211047556685 |
| 23 | 870385025022 |
| 24 | 3612193740355 |
| 25 | 15079839929453 |
| 26 | 63305470339527 |
| 27 | 267159465034792 |