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 | 3 |
| 3 | 10 |
| 4 | 32 |
| 5 | 106 |
| 6 | 357 |
| 7 | 1222 |
| 8 | 4230 |
| 9 | 14770 |
| 10 | 51918 |
| 11 | 183472 |
| 12 | 651191 |
| 13 | 2319626 |
| 14 | 8288135 |
| 15 | 29691760 |
| 16 | 106611596 |
| 17 | 383565754 |
| 18 | 1382423748 |
| 19 | 4990274016 |
| 20 | 18039252192 |
| 21 | 65292492328 |
| 22 | 236595647526 |
| 23 | 858231115540 |
| 24 | 3116138603103 |
| 25 | 11324267454946 |
| 26 | 41186435585589 |
| 27 | 149907159998452 |
| 28 | 545997804435897 |