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 | 15 |
| 5 | 53 |
| 6 | 214 |
| 7 | 960 |
| 8 | 4701 |
| 9 | 24873 |
| 10 | 141147 |
| 11 | 853641 |
| 12 | 5472642 |
| 13 | 37024569 |
| 14 | 263342224 |
| 15 | 1962835806 |
| 16 | 15288074104 |
| 17 | 124120865849 |
| 18 | 1048092680689 |
| 19 | 9186689045482 |
| 20 | 83435365244510 |
| 21 | 783923558286071 |
| 22 | 7608398620990535 |
| 23 | 76177574145052258 |
| 24 | 785853360840424425 |