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 | 9 |
| 2 | 56 |
| 3 | 279 |
| 4 | 1223 |
| 5 | 4932 |
| 6 | 18833 |
| 7 | 69345 |
| 8 | 249166 |
| 9 | 880525 |
| 10 | 3076295 |
| 11 | 10662459 |
| 12 | 36749785 |
| 13 | 126161246 |
| 14 | 431880044 |
| 15 | 1475412473 |
| 16 | 5032964258 |
| 17 | 17150277106 |
| 18 | 58395929325 |
| 19 | 198723871661 |
| 20 | 675989712225 |
| 21 | 2298799014859 |
| 22 | 7815699898677 |
| 23 | 26568450635871 |