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) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 9 |
| 6 | 21 |
| 7 | 55 |
| 8 | 146 |
| 9 | 413 |
| 10 | 1194 |
| 11 | 3553 |
| 12 | 10756 |
| 13 | 33134 |
| 14 | 103273 |
| 15 | 325484 |
| 16 | 1034734 |
| 17 | 3314870 |
| 18 | 10688513 |
| 19 | 34662777 |
| 20 | 112976023 |
| 21 | 369876832 |
| 22 | 1215811262 |
| 23 | 4010932603 |
| 24 | 13275356936 |
| 25 | 44070010202 |
| 26 | 146698487202 |
| 27 | 489550622528 |
| 28 | 1637472527602 |
| 29 | 5488829461525 |
| 30 | 18435194140301 |