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 | 3 |
| 3 | 8 |
| 4 | 21 |
| 5 | 57 |
| 6 | 157 |
| 7 | 438 |
| 8 | 1237 |
| 9 | 3530 |
| 10 | 10165 |
| 11 | 29505 |
| 12 | 86243 |
| 13 | 253654 |
| 14 | 750157 |
| 15 | 2229469 |
| 16 | 6655369 |
| 17 | 19946979 |
| 18 | 60000443 |
| 19 | 181076982 |
| 20 | 548125929 |
| 21 | 1663786344 |
| 22 | 5063133335 |
| 23 | 15444046031 |
| 24 | 47211447131 |
| 25 | 144614092732 |
| 26 | 443803262627 |
| 27 | 1364370846941 |
| 28 | 4201333752921 |
| 29 | 12957168021207 |