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 | 12 |
| 4 | 54 |
| 5 | 265 |
| 6 | 1373 |
| 7 | 7388 |
| 8 | 40888 |
| 9 | 231250 |
| 10 | 1330618 |
| 11 | 7764670 |
| 12 | 45841323 |
| 13 | 273316120 |
| 14 | 1643345418 |
| 15 | 9953021248 |
| 16 | 60665811025 |
| 17 | 371850104167 |
| 18 | 2290623433302 |
| 19 | 14173331572490 |
| 20 | 88049709138896 |
| 21 | 548978010516319 |
| 22 | 3434070688405887 |
| 23 | 21545961024510032 |